In the realm of nonlinear integrable systems,the presence of decompositions facilitates the establishment of linear superposition solutions and the derivation of novel coupled systems exhibiting nonlinear integrabilit...In the realm of nonlinear integrable systems,the presence of decompositions facilitates the establishment of linear superposition solutions and the derivation of novel coupled systems exhibiting nonlinear integrability.By focusing on single-component decompositions within the potential BKP hierarchy,it has been observed that specific linear superpositions of decomposition solutions remain consistent with the underlying equations.Moreover,through the implementation of multi-component decompositions within the potential BKP hierarchy,successful endeavors have been undertaken to formulate linear superposition solutions and novel coupled Kd V-type systems that resist decoupling via alterations in dependent variables.展开更多
Multi-component transition group metal borides(MMB_(2))have become a research hotspot due to their new composition design concepts and superior properties compared with conventional ceramics.Most of the current method...Multi-component transition group metal borides(MMB_(2))have become a research hotspot due to their new composition design concepts and superior properties compared with conventional ceramics.Most of the current methods,however,are complicated and time-consuming,the mass production remains a chal-lenge.Herein,we proposed a new high-efficiency strategy for synthesis of MMB_(2)using molten aluminum as the medium for the first time.The prepared Al-containing multi-component borides(TiZrHfNbTa)B_(2)microcrystals had a homogeneous composition with a hexagonal AlB_(2)structure and ultra-high hardness value of∼35.3 GPa,which was much higher than data reported in the literature and the rule of mix-ture estimations.Furthermore,combined with the First-principles calculation results,we found that the Poisson’s ratio(v)values exhibit a clearly ascending trend from 0.17 at VEC=3.5 to 0.18 at VEC=3.4,then to 0.201 at VEC=3.2 with the increasing of Al content.This indicates that the intrinsic toughness of multi-component boride microcrystals is obviously enhanced by the trace-doped Al elements.Besides,the fabricated Al-containing multi-component boride microcrystals have superior oxidation activation en-ergy and structural stability.The enhanced oxidation resistance is mainly attributed to the formation of a protective Al2 O3 oxide layer and the lattice distortion,both of which lead to sluggish diffusion of O_(2).These findings propose a new unexplored avenue for the fabrication of MMB_(2)materials with supe-rior comprehensive performance including ultra-hardness and intrinsically improved thermo-mechanical properties.展开更多
There remains debate on whether Mn is beneficial or detrimental to hydrogen embrittlement in stainless steel.In this work,a series of stainless steels were designed to study the change of hydrogen embrittlement sensit...There remains debate on whether Mn is beneficial or detrimental to hydrogen embrittlement in stainless steel.In this work,a series of stainless steels were designed to study the change of hydrogen embrittlement sensitivity,crack propagation,and hydrogen trapping behaviors upon Mn addition.The results suggest that adding 4 wt.% Mn increased hydrogen embrittlement susceptibility,whereas adding 8 wt.% Mn decreased hydrogen embrittlement sensitivity.Forming banded α’-martensite through austenitic grain is the main reason for the increased hydrogen embrittlement sensitivity when adding 4 wt.%Mn,by adsorbing hydrogen,promoting crack initiation,and accelerating crack propagation.展开更多
Based on the energy dissipation caused by consolidation deformation of the porous media under external force and migration of the internal suspended substances,a coupled multiphase-substance flow(CMF)model was establi...Based on the energy dissipation caused by consolidation deformation of the porous media under external force and migration of the internal suspended substances,a coupled multiphase-substance flow(CMF)model was established.This model introduced the new concepts,such as particle temperature and particle entropy,to describe energy dissipation at meso-level.This model used a potential energy density function and migration coefficients to establish the corresponding connection between the dissipative force and dissipative flow.This viewpoint unifies the deformation,seepage,and suspended substance migration of geotechnical materials under the framework of granular thermodynamics.It can reflect the evolution of effective stress in the solid matrix of multi-components in a particle-reorganized state,and considers the temperature driving effect.The proposed CMF model is validated using the experimental results under coupled migration of heavy metal ions(HMs)and suspended particles(SPs).The calculation results demonstrated that the CMF model can describe the flow process under the conditions of arbitrary changes in different suspended substance types,injection concentrations,and injection velocities.展开更多
A convenient photocatalytic multi-component reaction of alkenes,quinoxalin-2(1H)-ones,and diazo compounds has been developed in the presence of water.A number of ester-containing quinoxalin-2(1H)-ones could be efficie...A convenient photocatalytic multi-component reaction of alkenes,quinoxalin-2(1H)-ones,and diazo compounds has been developed in the presence of water.A number of ester-containing quinoxalin-2(1H)-ones could be efficiently obtained in moderate to good yields at room temperature.This metal-free visiblelight-driven tandem reaction was conducted through proton-coupled electron transfer(PCET)process using water as the hydrogen donor and 1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene(4CzIPN)as the photocatalyst.展开更多
Powder-Fueled Water Ramjet Engine(PFWRE)is of great attraction for high-speed and long-voyage underwater propulsion,as well as air–water trans-media navigation applications due to its high energy density and thrust a...Powder-Fueled Water Ramjet Engine(PFWRE)is of great attraction for high-speed and long-voyage underwater propulsion,as well as air–water trans-media navigation applications due to its high energy density and thrust adjustability.However,the complex multiphase combustion process in the combustor significantly affects engine performance.In this study,a detailed model for aluminum particle combustion in water vapor is developed and validated via literature data as well as the ground direct-connected test we conducted.Thereafter,the numerical study on the multiphase combustion process inside the aluminum-based PFWRE combustor is carried out within the Euler–Lagrange framework using the developed model.Results show that a reverse rotating vortex pair before the primary water injection causes particles to flow back towards the combustor head and leads to product deposition.Aluminum particles external to the powder jet have shorter preheating time than internal particles and burn out in advance.The analysis of the particle combustion process indicates that the flame structure inside the combustor consists of the particle preheating zone,the surface combustion heat release zone,the gas-phase combustion heat release zone,and the post-flame zone.In the present configuration,as the particle size increases from 10μm to 20μm,the preheating zone length increases from 35 mm to 85 mm.Meanwhile,heat release from gas-phase combustion decreases,and the average temperature of the combustor head first increases and then decreases.This study not only provides insight into the multiphase combustion characteristics of the aluminum-based PFWRE combustor but also offers guidance for the design of the combustion organization schemes and engine structure optimization.展开更多
Geological CO_(2) storage is a promising strategy for reducing greenhouse gas emissions;however,its underlying multiphase reactive flow mechanisms remain poorly understood.We conducted steady-state imbibition relative...Geological CO_(2) storage is a promising strategy for reducing greenhouse gas emissions;however,its underlying multiphase reactive flow mechanisms remain poorly understood.We conducted steady-state imbibition relative permeability experiments on sandstone from a proposed storage site,comple-mented by in situ X-ray imaging and ex situ analyses using scanning electron microscopy(SEM)and energy-dispersive X-ray spectroscopy(EDS).Despite our use of a brine that was pre-equilibrated with CO_(2),there was a significant reduction in both CO_(2) relative permeability and absolute permeability during multiphase flow due to chemical reactions.This reduction was driven by decreased pore and throat sizes,diminished connectivity,and increased irregularity of pore and throat shapes,as revealed by in situ pore-scale imaging.Mineral dissolution,primarily of feldspar,albite,and calcite,along with precipitation resulting from feldspar-to-kaolinite transformation and fines migration,were identified as contributing factors through SEM-EDS analysis.This work provides a benchmark for storage in mineralogically complex sandstones,for which the impact of chemical reactions on multiphase flow properties has been measured.展开更多
For the advancement of fast-charging sodium-ion batteries(SIBs),the synthesis of cutting-edge cathode materials with superior structural stability and enhanced Na+diffusion kinetics is imperative.Multiphase layered tr...For the advancement of fast-charging sodium-ion batteries(SIBs),the synthesis of cutting-edge cathode materials with superior structural stability and enhanced Na+diffusion kinetics is imperative.Multiphase layered transition metal oxides(LTMOs),which leverage the synergistic properties of two distinct monophasic LTMOs,have garnered significant attention;however,their efficacy under fast-charging conditions remains underexplored.In this study,we developed a high-throughput computational screening framework to identify optimal dopants that maximize the electrochemical performance of LTMOs.Specifically,we evaluated the efficacy of 32 dopants based on P2/O3-type Mn/Fe-based Na_(x)Mn_(0.5)Fe_(0.5)O_(2)(NMFO)cathode material.Multiphase LTMOs satisfying criteria for thermodynamic and structural stability,minimized phase transitions,and enhanced Na^(+)diffusion were systematically screened for their suitability in fast-charging applications.The analysis identified two dopants,Ti and Zr,which met all predefined screening criteria.Furthermore,we ranked and scored dopants based on their alignment with these criteria,establishing a comprehensive dopant performance database.These findings provide a robust foundation for experimental exploration and offer detailed guidelines for tailoring dopants to optimize fast-charging SIBs.展开更多
Multiphase flows widely exist in various scientific and engineering fields,and strongly compressible multiphase flows commonly occur in practical applications,which makes them an important part of computational fluid ...Multiphase flows widely exist in various scientific and engineering fields,and strongly compressible multiphase flows commonly occur in practical applications,which makes them an important part of computational fluid dynamics.In this study,an axisymmetric adaptive multiresolution smooth particle hydrodynamics(SPH)model is proposed to solve various strongly compressible multiphase flow problems.In the present model,the governing equations are discretized in cylindrical polar coordinates,and an improved volume adaptive scheme is developed to better solve the problem of excessive volume change in strongly compressible multiphase flows.On this basis,combined with the adaptive particle refinement technique,an adaptive multiresolution scheme is proposed in this study.In addition,the high-order differential operator and diffusion correction term are utilized to improve the accuracy and stability.The effectiveness of the model is verified by testing four typical strongly compressible multiphase flow problems.By comparing the results of adaptive multiresolution SPH with other numerical results or experimental data,we can conclude that the present SPH method effectively models strongly compressible multiphase flows.展开更多
Hydrate phase transition may pose risks in pipeline blockage and severe challenges for offshore natural gas hydrate pro-duction.The present work involves the development of a multiphase gas-liquid-solid vertical slug ...Hydrate phase transition may pose risks in pipeline blockage and severe challenges for offshore natural gas hydrate pro-duction.The present work involves the development of a multiphase gas-liquid-solid vertical slug flow hydrodynamic model consi-dering hydrate phase transition kinetics with heat and mass transfer behaviors.The varying gas physical properties due to pressure and temperature variations are also introduced to evaluate vertical slug flow characteristics.The proposed model is used to carry out a series of numerical simulations to examine the interactions between hydrate phase transition and vertical slug flow hydrodynamics.Furthermore,the hydrate volumetric fractions under different pressure and temperature conditions are predicted.The results reveal that hydrate formation and gas expansion cause the mixture superficial velocity,and the gas and liquid fractions,void fraction in liq-uid slug,and unit length tend to decrease.The increase in outlet pressure leads to an increased hydrate formation rate,which not only increases the hydrate volumetric fraction along the pipe but also causes the upward shift of the hydrate phase transition critical point.展开更多
A 3D mathematical model was proposed to investigate the molten steel–slag–air multiphase flow in a two-strand slab continuous casting(CC)tundish during ladle change.The study focused on the exposure of the molten st...A 3D mathematical model was proposed to investigate the molten steel–slag–air multiphase flow in a two-strand slab continuous casting(CC)tundish during ladle change.The study focused on the exposure of the molten steel and the subsequent reoxidation occurrence.The exposure of the molten steel was calculated using the coupled realizable k–εmodel and volume of fluid(VOF)model.The diffusion of dissolved oxygen was determined by solving the user-defined scalar(UDS)equation.Moreover,the user-defined function(UDF)was used to describe the source term in the UDS equation and determine the oxidation rate and oxidation position.The effect of the refilling speed on the molten steel exposure and dissolved oxygen content was also discussed.Increasing the refilling speed during ladle change reduced the refilling time and the exposure duration of the molten steel.However,the elevated refilling speed enlarged the slag eyes and increased the average dissolved oxygen content within the tundish,thereby exacerbating the reoxidation phenomenon.In addition,the time required for the molten steel with a high dissolved oxygen content to exit the tundish varied with the refilling speed.When the inlet speed was 3.0 m·s^(-1)during ladle change,the molten steel with a high dissolved oxygen content exited the outlet in a short period,reaching a maximum dissolved oxygen content of 0.000525wt%.Conversely,when the inlet speed was 1.8 m·s^(-1),the maximum dissolved oxygen content was 0.000382wt%.The refilling speed during the ladle change process must be appropriately decreased to minimize reoxidation effects and enhance the steel product quality.展开更多
This paper aims to tackle the calculation efficiency problem raised in the cavitation-flow simulation of the aviation centrifugal pump due to the fading-away interface resulting from the dissipation of numerics used i...This paper aims to tackle the calculation efficiency problem raised in the cavitation-flow simulation of the aviation centrifugal pump due to the fading-away interface resulting from the dissipation of numerics used in the phase-change control equation for unstructured-grid multiphase flow,and due to the limitation of flow time-step in whole flow regimes,the control equation of vapor–liquid two-phase flow considering cavitation mass transport is established firstly,modifying the momentum equation by introducing the surface tension,and adding the artificial convective flow to the phase equation to solve the numerical dissipation problem.Secondly,in consideration of the local time step principle and based on the multi-dimensional general limiter algorithm with explicit solutions under the OpenFOAM platform,a solution method of steady-state VOF (Volume of Fluid) model considering cavitation two-phase change is constructed,and the feasibility of this method is verified by NACA hydrofoil and NASA flat plate inducer.Finally,based on the platform developed,the cavitation performance of an aviation centrifugal pump inducer is analyzed.The research results show that the error of the calculated cavitation pressure distribution for NACA hydrofoil between the simulation test and the experimental-test is less than 5%,and the maximum error of calculated cavitation number at pump head dropping for NASA high-speed flat plate inducer between the simulation test and the experimental-test is 2.1%.The cavitation area observed in the simulation test is the same as that obtained in the high-speed photography test.Based on the OpenFOAM simulation method,the position of pump head dropping of the fuel centrifugal pump can be accurately captured.The error of the calculated cavitation number at pump head dropping between the simulation test and the experimental test is about 3.7%,showing high calculation accuracy.展开更多
A multiphase field model coupled with a lattice Boltzmann(PF-LBM)model is proposed to simulate the distribution mechanism of bubbles and solutes at the solid-liquid interface,the interaction between dendrites and bubb...A multiphase field model coupled with a lattice Boltzmann(PF-LBM)model is proposed to simulate the distribution mechanism of bubbles and solutes at the solid-liquid interface,the interaction between dendrites and bubbles,and the effects of different temperatures,anisotropic strengths and tilting angles on the solidified organization of the SCN-0.24wt.%butanedinitrile alloy during the solidification process.The model adopts a multiphase field model to simulate the growth of dendrites,calculates the growth motions of dendrites based on the interfacial solute equilibrium;and adopts a lattice Boltzmann model(LBM)based on the Shan-Chen multiphase flow to simulate the growth and motions of bubbles in the liquid phase,which includes the interaction between solid-liquid-gas phases.The simulation results show that during the directional growth of columnar dendrites,bubbles first precipitate out slowly at the very bottom of the dendrites,and then rise up due to the different solid-liquid densities and pressure differences.The bubbles will interact with the dendrite in the process of flow migration,such as extrusion,overflow,fusion and disappearance.In the case of wide gaps in the dendrite channels,bubbles will fuse to form larger irregular bubbles,and in the case of dense channels,bubbles will deform due to the extrusion of dendrites.In the simulated region,as the dendrites converge and diverge,the bubbles precipitate out of the dendrites by compression and diffusion,which also causes physical phenomena such as fusion and spillage of the bubbles.These results reveal the physical mechanisms of bubble nucleation,growth and kinematic evolution during solidification and interaction with dendrite growth.展开更多
Macrosegregation is a critical factor that limits the mechanical properties of materials.The impact of equiaxed crystal sedimentation on macrosegregation has been extensively studied,as it plays a significant role in ...Macrosegregation is a critical factor that limits the mechanical properties of materials.The impact of equiaxed crystal sedimentation on macrosegregation has been extensively studied,as it plays a significant role in determining the distribution of alloying elements and impurities within a material.To improve macrosegregation in steel connecting shafts,a multiphase solidification model that couples melt flow,heat transfer,microstructure evolution,and solute transport was established based on the volume-averaged Eulerian-Eulerian approach.In this model,the effects of liquid phase,equiaxed crystals,columnar dendrites,and columnar-to-equiaxed transition(CET)during solidification and evolution of microstructure can be considered simultaneously.The sedimentation of equiaxed crystals contributes to negative macrosegregation,where regions between columnar dendrites and equiaxed crystals undergo significant A-type positive macrosegregation due to the CET.Additionally,noticeable positive macrosegregation occurs in the area of final solidification in the ingot.The improvement in macrosegregation is beneficial for enhancing the mechanical properties of connecting shafts.To mitigate the thermal convection of molten steel resulting from excessive superheating,reducing the superheating during casting without employing external fields or altering the design of the ingot mold is indeed an effective approach to control macrosegregation.展开更多
Multiphase microstructure significantly increases the strength,usually at the expense of flangeability because of lacking microstructure homogeneity.To further improve the strength-flangeability of multiphase steel,th...Multiphase microstructure significantly increases the strength,usually at the expense of flangeability because of lacking microstructure homogeneity.To further improve the strength-flangeability of multiphase steel,the microstructural homogeneity was advanced by adjusting the hard martensite/austenite(M/A)islands.The strength-flangeability was measured via uniaxial tensile tests and hole expansion tests.Their microstructures were characterized using a scanning electron microscope equipped with an electron backscatter diffraction detector and a transmission electron microscope.Nanoindentation tests were supplementally used to quantitatively reveal the microstructural homogeneity of the steels.Results show that the adjusted multiphase steel achieves an excellent ultimate tensile strength(~800 MPa)and flangeability(~135%hole expansion ratio).A promising homogeneous multiphase microstructure was obtained by controlling undercooled austenite transformed at about 600℃.This microstructure consists of soft polygonal ferrite,blocky bainitic ferrite,and hard M/A islands.The volume fraction of M/A islands is around 5%,and the average size is less than l pm.Detailed nanoindentation analysis indicated that the participation of M/A islands impressively influenced the microstructural homogeneity.Weakened strain partition and better mechanical compatibility were present in the adjusted multiphase steel since the plasticity initiation started late,which resulted in a positive flangeability.Moreover,avoiding M/A islands distributed in the chain along the rolling direction on the matrix hindered the possibility of voids coalescing into cracks and stabilized the flanging performance.展开更多
Multiphase design is a promising approach to achieve superior ablation resistance of multicomponent ultra-high temperature ceramic,while understanding the ablation mechanism is the foundation.Here,through investigatin...Multiphase design is a promising approach to achieve superior ablation resistance of multicomponent ultra-high temperature ceramic,while understanding the ablation mechanism is the foundation.Here,through investigating a three-phase multicomponent ceramic consisting of Hf-rich carbide,Nb-rich carbide,and Zr-rich silicide phases,we report a newly discovered solid-state reaction process among multiphase multicomponent ceramic during ablation.It was found that this solid-state reaction occurred in the matrix/oxide scale interface region.In this process,metal cations are counter-diffused between the multicomponent phases,thereby resulting in their composition evolution,which allows the multicomponent phases to exist stably under a higher oxygen partial pressure,leading to the improvement of thermodynamic stability of three-phase multicomponent ceramic.Additionally,this solid-state reaction process appears synergistic with the preferential oxidation behavior among the oxide scale in enhancing the ablation performance.展开更多
Stainless steels are used in a wide range of complex environments due to their excellent corrosion resistance.Multiphase stainless steels can offer an excellent combination of strength,toughness and corrosion resistan...Stainless steels are used in a wide range of complex environments due to their excellent corrosion resistance.Multiphase stainless steels can offer an excellent combination of strength,toughness and corrosion resistance due to the coexistence of different microstructures.The microstructure and mechanical properties of a novel cast multiphase stainless steel,composed of martensite,ferrite,and austenite,were investigated following appropriate heat treatment processes:solution treatment at 1,050℃ for 0.5 h followed by water quenching to room temperature,and aging treatment at 500℃ for 4 h followed by water quenching to room temperature.Results show reversed austenite is formed by diffusion of Ni element during aging process,and the enrichment of Ni atoms directly determines the mechanical stability of austenite.The austenite with a lower Ni content undergoes a martensitic transformation during plastic deformation.The tensile strength of the specimen exceeds 1,100 MPa and the elongation exceeds 24%after solid solution,and further increases to 1,247 MPa and 25%after aging treatment.This enhancement is due to the TRIP effect of austenite and the precipitation of the nanoscale G-phase pinning dislocations in ferrite and martensite.展开更多
During perfusion culture,the growth of bone tissues in the scaffold was closely related to the locations of initial adhered cells and their density.In this study,the fluid mechanical responses of Voronoi-lattice scaff...During perfusion culture,the growth of bone tissues in the scaffold was closely related to the locations of initial adhered cells and their density.In this study,the fluid mechanical responses of Voronoi-lattice scaffolds and initial adhered cells on scaffolds were quantitatively investigated.Multiphase fluid-structure interaction(FSI)model was verified by comparing with the results of Diamond scaffolds culture in the literature.Fluid mechanical responses of Voronoi-lattice scaffolds and cells were analyzed by multiphase FSI model.Regression equations were established by response surface method(RSM)to determine relationships between structural design factors of Voronoi-lattice scaffolds and fluid mechanical response parameters of scaffolds and cells.The results showed that the percentage of adhered cells and the locations of initial adhered cells obtained by multiphase FSI model of Diamond scaffolds had the same trend with that obtained by perfusion culture.Regression equations established based on RSM could well predict the fluid mechanical response parameters of Voronoi-scaffolds and cells.The multiphase FSI model closely related the densities of cells and the locations of adhered cells to bone tissue growth.The model could provide a certain theoretical basis for constructing and culturing engineered bone tissues in vitro perfusion.展开更多
In recent years, antibiotic pollution has become a serious threat to human health. In this study, a gas-liquid discharge plasma is developed to degrade ciprofloxacin hydrochloride in a multiphase mixed system containi...In recent years, antibiotic pollution has become a serious threat to human health. In this study, a gas-liquid discharge plasma is developed to degrade ciprofloxacin hydrochloride in a multiphase mixed system containing inorganic and organic impurities. The discharge characteristics are analyzed by diagnosing the applied voltage and discharge current waveforms, as well as the optical emission spectra. The work investigates how degradation efficiency is affected by applied voltage, gas flow rate, treatment time, initial concentration as well as the addition of γ-Al_(2)O_(3) pellets and peanut straw. After 70 min, the degradation efficiency of ciprofloxacin hydrochloride in the multiphase mixed system reached 99.6%. Its removal efficiency increases as the initial concentration decreases and the applied voltage increases. Besides, there is still a good degradation efficiency of ciprofloxacin hydrochloride with the addition of peanut straw.The degradation mechanism of ciprofloxacin hydrochloride is investigated through the analysis of degraded intermediates and reactive species.展开更多
The spiral-wound heat exchanger(SWHE) is the primary low-temperature heat exchanger for large-scale LNG plants due to its high-pressure resistance, compact structure, and high heat exchange efficiency. This paper stud...The spiral-wound heat exchanger(SWHE) is the primary low-temperature heat exchanger for large-scale LNG plants due to its high-pressure resistance, compact structure, and high heat exchange efficiency. This paper studied the shell-side heat and mass transfer characteristics of vapor-liquid two-phase mixed refrigerants in an SWHE by combining a multi-component model in FLUENT software with a customized multicomponent mass transfer model. Besides, the mathematical model under the sloshing condition was obtained through mathematical derivation, and the corresponding UDF code was loaded into FLUENT as the momentum source term. The results under the sloshing conditions were compared with the relevant parameters under the steady-state condition. The shell-side heat and mass transfer characteristics of the SWHE were investigated by adjusting the component ratio and other working conditions. It was found that the sloshing conditions enhance the heat transfer performance and sometimes have insignificant effects. The sloshing condition is beneficial to reduce the flow resistance. The comprehensive performance of multi-component refrigerants has been improved and the improvement is more significant under sloshing conditions, considering both the heat transfer and pressure drop.These results will provide theoretical support for the research and design of multi-component heat and mass transfer enhancement of LNG SWHE under ocean sloshing conditions.展开更多
基金sponsored by the National Natural Science Foundations of China under Grant Nos.12301315,12235007,11975131the Zhejiang Provincial Natural Science Foundation of China under Grant No.LQ20A010009。
文摘In the realm of nonlinear integrable systems,the presence of decompositions facilitates the establishment of linear superposition solutions and the derivation of novel coupled systems exhibiting nonlinear integrability.By focusing on single-component decompositions within the potential BKP hierarchy,it has been observed that specific linear superpositions of decomposition solutions remain consistent with the underlying equations.Moreover,through the implementation of multi-component decompositions within the potential BKP hierarchy,successful endeavors have been undertaken to formulate linear superposition solutions and novel coupled Kd V-type systems that resist decoupling via alterations in dependent variables.
基金financially supported by the National Natural Science Foundation of China(Nos.52271033 and 52071179)the Key program of National Natural Science Foundation of China(No.51931003)+2 种基金Natural Science Foundation of Jiangsu Province,China(No.BK20221493)Jiangsu Province Leading Edge Technology Basic Research Major Project(No.BK20222014)Foundation of“Qinglan Project”for Colleges and Universities in Jiangsu Province.
文摘Multi-component transition group metal borides(MMB_(2))have become a research hotspot due to their new composition design concepts and superior properties compared with conventional ceramics.Most of the current methods,however,are complicated and time-consuming,the mass production remains a chal-lenge.Herein,we proposed a new high-efficiency strategy for synthesis of MMB_(2)using molten aluminum as the medium for the first time.The prepared Al-containing multi-component borides(TiZrHfNbTa)B_(2)microcrystals had a homogeneous composition with a hexagonal AlB_(2)structure and ultra-high hardness value of∼35.3 GPa,which was much higher than data reported in the literature and the rule of mix-ture estimations.Furthermore,combined with the First-principles calculation results,we found that the Poisson’s ratio(v)values exhibit a clearly ascending trend from 0.17 at VEC=3.5 to 0.18 at VEC=3.4,then to 0.201 at VEC=3.2 with the increasing of Al content.This indicates that the intrinsic toughness of multi-component boride microcrystals is obviously enhanced by the trace-doped Al elements.Besides,the fabricated Al-containing multi-component boride microcrystals have superior oxidation activation en-ergy and structural stability.The enhanced oxidation resistance is mainly attributed to the formation of a protective Al2 O3 oxide layer and the lattice distortion,both of which lead to sluggish diffusion of O_(2).These findings propose a new unexplored avenue for the fabrication of MMB_(2)materials with supe-rior comprehensive performance including ultra-hardness and intrinsically improved thermo-mechanical properties.
基金supported by the National Science and Technology Resources Investigation Program of China(Grant No.2021FY100604).
文摘There remains debate on whether Mn is beneficial or detrimental to hydrogen embrittlement in stainless steel.In this work,a series of stainless steels were designed to study the change of hydrogen embrittlement sensitivity,crack propagation,and hydrogen trapping behaviors upon Mn addition.The results suggest that adding 4 wt.% Mn increased hydrogen embrittlement susceptibility,whereas adding 8 wt.% Mn decreased hydrogen embrittlement sensitivity.Forming banded α’-martensite through austenitic grain is the main reason for the increased hydrogen embrittlement sensitivity when adding 4 wt.%Mn,by adsorbing hydrogen,promoting crack initiation,and accelerating crack propagation.
基金supported by the National Natural Science Foundation of China(Grant Nos.52378321 and 52079003).
文摘Based on the energy dissipation caused by consolidation deformation of the porous media under external force and migration of the internal suspended substances,a coupled multiphase-substance flow(CMF)model was established.This model introduced the new concepts,such as particle temperature and particle entropy,to describe energy dissipation at meso-level.This model used a potential energy density function and migration coefficients to establish the corresponding connection between the dissipative force and dissipative flow.This viewpoint unifies the deformation,seepage,and suspended substance migration of geotechnical materials under the framework of granular thermodynamics.It can reflect the evolution of effective stress in the solid matrix of multi-components in a particle-reorganized state,and considers the temperature driving effect.The proposed CMF model is validated using the experimental results under coupled migration of heavy metal ions(HMs)and suspended particles(SPs).The calculation results demonstrated that the CMF model can describe the flow process under the conditions of arbitrary changes in different suspended substance types,injection concentrations,and injection velocities.
基金supported by Sichuan Science and Technology Program(No.2023NSFSC0101)the 2024 Provincial platform project of Chengdu Normal University(No.GNFZ202404)+1 种基金Natural Science Foundation of Shandong Province(No.ZR2021MB065)National Natural Science Foundation of China(No.22101237)。
文摘A convenient photocatalytic multi-component reaction of alkenes,quinoxalin-2(1H)-ones,and diazo compounds has been developed in the presence of water.A number of ester-containing quinoxalin-2(1H)-ones could be efficiently obtained in moderate to good yields at room temperature.This metal-free visiblelight-driven tandem reaction was conducted through proton-coupled electron transfer(PCET)process using water as the hydrogen donor and 1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene(4CzIPN)as the photocatalyst.
基金supported by the National Natural Science Foundation of China(No.22305053).
文摘Powder-Fueled Water Ramjet Engine(PFWRE)is of great attraction for high-speed and long-voyage underwater propulsion,as well as air–water trans-media navigation applications due to its high energy density and thrust adjustability.However,the complex multiphase combustion process in the combustor significantly affects engine performance.In this study,a detailed model for aluminum particle combustion in water vapor is developed and validated via literature data as well as the ground direct-connected test we conducted.Thereafter,the numerical study on the multiphase combustion process inside the aluminum-based PFWRE combustor is carried out within the Euler–Lagrange framework using the developed model.Results show that a reverse rotating vortex pair before the primary water injection causes particles to flow back towards the combustor head and leads to product deposition.Aluminum particles external to the powder jet have shorter preheating time than internal particles and burn out in advance.The analysis of the particle combustion process indicates that the flame structure inside the combustor consists of the particle preheating zone,the surface combustion heat release zone,the gas-phase combustion heat release zone,and the post-flame zone.In the present configuration,as the particle size increases from 10μm to 20μm,the preheating zone length increases from 35 mm to 85 mm.Meanwhile,heat release from gas-phase combustion decreases,and the average temperature of the combustor head first increases and then decreases.This study not only provides insight into the multiphase combustion characteristics of the aluminum-based PFWRE combustor but also offers guidance for the design of the combustion organization schemes and engine structure optimization.
文摘Geological CO_(2) storage is a promising strategy for reducing greenhouse gas emissions;however,its underlying multiphase reactive flow mechanisms remain poorly understood.We conducted steady-state imbibition relative permeability experiments on sandstone from a proposed storage site,comple-mented by in situ X-ray imaging and ex situ analyses using scanning electron microscopy(SEM)and energy-dispersive X-ray spectroscopy(EDS).Despite our use of a brine that was pre-equilibrated with CO_(2),there was a significant reduction in both CO_(2) relative permeability and absolute permeability during multiphase flow due to chemical reactions.This reduction was driven by decreased pore and throat sizes,diminished connectivity,and increased irregularity of pore and throat shapes,as revealed by in situ pore-scale imaging.Mineral dissolution,primarily of feldspar,albite,and calcite,along with precipitation resulting from feldspar-to-kaolinite transformation and fines migration,were identified as contributing factors through SEM-EDS analysis.This work provides a benchmark for storage in mineralogically complex sandstones,for which the impact of chemical reactions on multiphase flow properties has been measured.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIT)(No.2022R1F1A1074339)。
文摘For the advancement of fast-charging sodium-ion batteries(SIBs),the synthesis of cutting-edge cathode materials with superior structural stability and enhanced Na+diffusion kinetics is imperative.Multiphase layered transition metal oxides(LTMOs),which leverage the synergistic properties of two distinct monophasic LTMOs,have garnered significant attention;however,their efficacy under fast-charging conditions remains underexplored.In this study,we developed a high-throughput computational screening framework to identify optimal dopants that maximize the electrochemical performance of LTMOs.Specifically,we evaluated the efficacy of 32 dopants based on P2/O3-type Mn/Fe-based Na_(x)Mn_(0.5)Fe_(0.5)O_(2)(NMFO)cathode material.Multiphase LTMOs satisfying criteria for thermodynamic and structural stability,minimized phase transitions,and enhanced Na^(+)diffusion were systematically screened for their suitability in fast-charging applications.The analysis identified two dopants,Ti and Zr,which met all predefined screening criteria.Furthermore,we ranked and scored dopants based on their alignment with these criteria,establishing a comprehensive dopant performance database.These findings provide a robust foundation for experimental exploration and offer detailed guidelines for tailoring dopants to optimize fast-charging SIBs.
基金Supported by the Guangxi Natural Science Foundation(Grant No.2021GXNSFBA196008)the Guangxi Science and Technology Development Program(Grant No.GuikeAD22035189).
文摘Multiphase flows widely exist in various scientific and engineering fields,and strongly compressible multiphase flows commonly occur in practical applications,which makes them an important part of computational fluid dynamics.In this study,an axisymmetric adaptive multiresolution smooth particle hydrodynamics(SPH)model is proposed to solve various strongly compressible multiphase flow problems.In the present model,the governing equations are discretized in cylindrical polar coordinates,and an improved volume adaptive scheme is developed to better solve the problem of excessive volume change in strongly compressible multiphase flows.On this basis,combined with the adaptive particle refinement technique,an adaptive multiresolution scheme is proposed in this study.In addition,the high-order differential operator and diffusion correction term are utilized to improve the accuracy and stability.The effectiveness of the model is verified by testing four typical strongly compressible multiphase flow problems.By comparing the results of adaptive multiresolution SPH with other numerical results or experimental data,we can conclude that the present SPH method effectively models strongly compressible multiphase flows.
基金supported by the National Natural Science Foundation of China(No.52301355)the Natu-ral Science Foundation of Qingdao Municipality(No.23-2-1-108-zyyd-jch)the China University of Petroleum(East China)Independent Innovation Research Project(Science and Engineering)-Leading Talent Cultivation Fund(No.24CX07001A).
文摘Hydrate phase transition may pose risks in pipeline blockage and severe challenges for offshore natural gas hydrate pro-duction.The present work involves the development of a multiphase gas-liquid-solid vertical slug flow hydrodynamic model consi-dering hydrate phase transition kinetics with heat and mass transfer behaviors.The varying gas physical properties due to pressure and temperature variations are also introduced to evaluate vertical slug flow characteristics.The proposed model is used to carry out a series of numerical simulations to examine the interactions between hydrate phase transition and vertical slug flow hydrodynamics.Furthermore,the hydrate volumetric fractions under different pressure and temperature conditions are predicted.The results reveal that hydrate formation and gas expansion cause the mixture superficial velocity,and the gas and liquid fractions,void fraction in liq-uid slug,and unit length tend to decrease.The increase in outlet pressure leads to an increased hydrate formation rate,which not only increases the hydrate volumetric fraction along the pipe but also causes the upward shift of the hydrate phase transition critical point.
基金the National Key R&D Program(No.2023YFB3709900)the National Natural Science Foundation of China(Nos.U22A20171 and 52104343)the High Steel Central(HSC)at North China University of Science and Technology and Yanshan Univ ersity,China。
文摘A 3D mathematical model was proposed to investigate the molten steel–slag–air multiphase flow in a two-strand slab continuous casting(CC)tundish during ladle change.The study focused on the exposure of the molten steel and the subsequent reoxidation occurrence.The exposure of the molten steel was calculated using the coupled realizable k–εmodel and volume of fluid(VOF)model.The diffusion of dissolved oxygen was determined by solving the user-defined scalar(UDS)equation.Moreover,the user-defined function(UDF)was used to describe the source term in the UDS equation and determine the oxidation rate and oxidation position.The effect of the refilling speed on the molten steel exposure and dissolved oxygen content was also discussed.Increasing the refilling speed during ladle change reduced the refilling time and the exposure duration of the molten steel.However,the elevated refilling speed enlarged the slag eyes and increased the average dissolved oxygen content within the tundish,thereby exacerbating the reoxidation phenomenon.In addition,the time required for the molten steel with a high dissolved oxygen content to exit the tundish varied with the refilling speed.When the inlet speed was 3.0 m·s^(-1)during ladle change,the molten steel with a high dissolved oxygen content exited the outlet in a short period,reaching a maximum dissolved oxygen content of 0.000525wt%.Conversely,when the inlet speed was 1.8 m·s^(-1),the maximum dissolved oxygen content was 0.000382wt%.The refilling speed during the ladle change process must be appropriately decreased to minimize reoxidation effects and enhance the steel product quality.
基金supported by the National Science and Technology Major Project, China (No. J2019-V-0016-0111)the Aviation Engine and Gas Turbine Basic Science Center Project, China (No. P2022-B-V-003-001)+3 种基金the Defense Industrial Technology Development Program, China (No. JCKY2022607C002)the AECC Industry University Cooperation Project, China (No. HFZL2022CXY013)the National Natural Science Foundation of China (No. 52372396)the Key R&D Project in Shaanxi Province, China (No. 2021GXLH-01-16)。
文摘This paper aims to tackle the calculation efficiency problem raised in the cavitation-flow simulation of the aviation centrifugal pump due to the fading-away interface resulting from the dissipation of numerics used in the phase-change control equation for unstructured-grid multiphase flow,and due to the limitation of flow time-step in whole flow regimes,the control equation of vapor–liquid two-phase flow considering cavitation mass transport is established firstly,modifying the momentum equation by introducing the surface tension,and adding the artificial convective flow to the phase equation to solve the numerical dissipation problem.Secondly,in consideration of the local time step principle and based on the multi-dimensional general limiter algorithm with explicit solutions under the OpenFOAM platform,a solution method of steady-state VOF (Volume of Fluid) model considering cavitation two-phase change is constructed,and the feasibility of this method is verified by NACA hydrofoil and NASA flat plate inducer.Finally,based on the platform developed,the cavitation performance of an aviation centrifugal pump inducer is analyzed.The research results show that the error of the calculated cavitation pressure distribution for NACA hydrofoil between the simulation test and the experimental-test is less than 5%,and the maximum error of calculated cavitation number at pump head dropping for NASA high-speed flat plate inducer between the simulation test and the experimental-test is 2.1%.The cavitation area observed in the simulation test is the same as that obtained in the high-speed photography test.Based on the OpenFOAM simulation method,the position of pump head dropping of the fuel centrifugal pump can be accurately captured.The error of the calculated cavitation number at pump head dropping between the simulation test and the experimental test is about 3.7%,showing high calculation accuracy.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.52161002,51661020,and 11364024)the Postdoctoral Science Foundation of China(Grant No.2014M560371)the Funds for Distinguished Young Scientists of Lanzhou University of Technology of China(Grant No.J201304).
文摘A multiphase field model coupled with a lattice Boltzmann(PF-LBM)model is proposed to simulate the distribution mechanism of bubbles and solutes at the solid-liquid interface,the interaction between dendrites and bubbles,and the effects of different temperatures,anisotropic strengths and tilting angles on the solidified organization of the SCN-0.24wt.%butanedinitrile alloy during the solidification process.The model adopts a multiphase field model to simulate the growth of dendrites,calculates the growth motions of dendrites based on the interfacial solute equilibrium;and adopts a lattice Boltzmann model(LBM)based on the Shan-Chen multiphase flow to simulate the growth and motions of bubbles in the liquid phase,which includes the interaction between solid-liquid-gas phases.The simulation results show that during the directional growth of columnar dendrites,bubbles first precipitate out slowly at the very bottom of the dendrites,and then rise up due to the different solid-liquid densities and pressure differences.The bubbles will interact with the dendrite in the process of flow migration,such as extrusion,overflow,fusion and disappearance.In the case of wide gaps in the dendrite channels,bubbles will fuse to form larger irregular bubbles,and in the case of dense channels,bubbles will deform due to the extrusion of dendrites.In the simulated region,as the dendrites converge and diverge,the bubbles precipitate out of the dendrites by compression and diffusion,which also causes physical phenomena such as fusion and spillage of the bubbles.These results reveal the physical mechanisms of bubble nucleation,growth and kinematic evolution during solidification and interaction with dendrite growth.
基金supported by the National Key Research and Development Program of China(2021YFB3702005)the National Natural Science Foundation of China(52304352)+3 种基金the Central Government Guides Local Science and Technology Development Fund Projects(2023JH6/100100046)2022"Chunhui Program"Collaborative Scientific Research Project(202200042)the Doctoral Start-up Foundation of Liaoning Province(2023-BS-182)the Technology Development Project of State Key Laboratory of Metal Material for Marine Equipment and Application[HGSKL-USTLN(2022)01].
文摘Macrosegregation is a critical factor that limits the mechanical properties of materials.The impact of equiaxed crystal sedimentation on macrosegregation has been extensively studied,as it plays a significant role in determining the distribution of alloying elements and impurities within a material.To improve macrosegregation in steel connecting shafts,a multiphase solidification model that couples melt flow,heat transfer,microstructure evolution,and solute transport was established based on the volume-averaged Eulerian-Eulerian approach.In this model,the effects of liquid phase,equiaxed crystals,columnar dendrites,and columnar-to-equiaxed transition(CET)during solidification and evolution of microstructure can be considered simultaneously.The sedimentation of equiaxed crystals contributes to negative macrosegregation,where regions between columnar dendrites and equiaxed crystals undergo significant A-type positive macrosegregation due to the CET.Additionally,noticeable positive macrosegregation occurs in the area of final solidification in the ingot.The improvement in macrosegregation is beneficial for enhancing the mechanical properties of connecting shafts.To mitigate the thermal convection of molten steel resulting from excessive superheating,reducing the superheating during casting without employing external fields or altering the design of the ingot mold is indeed an effective approach to control macrosegregation.
基金financial support from the National Natural Science Foundation of China (Grant Nos.52274372 and 52201101)the National Key R&D Program of China (2021YFB3702404)the Fundamental Research Funds for the Central Universities (FRF-TP-22-013A1).
文摘Multiphase microstructure significantly increases the strength,usually at the expense of flangeability because of lacking microstructure homogeneity.To further improve the strength-flangeability of multiphase steel,the microstructural homogeneity was advanced by adjusting the hard martensite/austenite(M/A)islands.The strength-flangeability was measured via uniaxial tensile tests and hole expansion tests.Their microstructures were characterized using a scanning electron microscope equipped with an electron backscatter diffraction detector and a transmission electron microscope.Nanoindentation tests were supplementally used to quantitatively reveal the microstructural homogeneity of the steels.Results show that the adjusted multiphase steel achieves an excellent ultimate tensile strength(~800 MPa)and flangeability(~135%hole expansion ratio).A promising homogeneous multiphase microstructure was obtained by controlling undercooled austenite transformed at about 600℃.This microstructure consists of soft polygonal ferrite,blocky bainitic ferrite,and hard M/A islands.The volume fraction of M/A islands is around 5%,and the average size is less than l pm.Detailed nanoindentation analysis indicated that the participation of M/A islands impressively influenced the microstructural homogeneity.Weakened strain partition and better mechanical compatibility were present in the adjusted multiphase steel since the plasticity initiation started late,which resulted in a positive flangeability.Moreover,avoiding M/A islands distributed in the chain along the rolling direction on the matrix hindered the possibility of voids coalescing into cracks and stabilized the flanging performance.
基金supported by the National Natural Science Foundation of China(52072410 and 51602349).
文摘Multiphase design is a promising approach to achieve superior ablation resistance of multicomponent ultra-high temperature ceramic,while understanding the ablation mechanism is the foundation.Here,through investigating a three-phase multicomponent ceramic consisting of Hf-rich carbide,Nb-rich carbide,and Zr-rich silicide phases,we report a newly discovered solid-state reaction process among multiphase multicomponent ceramic during ablation.It was found that this solid-state reaction occurred in the matrix/oxide scale interface region.In this process,metal cations are counter-diffused between the multicomponent phases,thereby resulting in their composition evolution,which allows the multicomponent phases to exist stably under a higher oxygen partial pressure,leading to the improvement of thermodynamic stability of three-phase multicomponent ceramic.Additionally,this solid-state reaction process appears synergistic with the preferential oxidation behavior among the oxide scale in enhancing the ablation performance.
基金supported by the Inner Mongolia Autonomous Region Science and Technology Major Special Project(Grant No.2021SZD0082).
文摘Stainless steels are used in a wide range of complex environments due to their excellent corrosion resistance.Multiphase stainless steels can offer an excellent combination of strength,toughness and corrosion resistance due to the coexistence of different microstructures.The microstructure and mechanical properties of a novel cast multiphase stainless steel,composed of martensite,ferrite,and austenite,were investigated following appropriate heat treatment processes:solution treatment at 1,050℃ for 0.5 h followed by water quenching to room temperature,and aging treatment at 500℃ for 4 h followed by water quenching to room temperature.Results show reversed austenite is formed by diffusion of Ni element during aging process,and the enrichment of Ni atoms directly determines the mechanical stability of austenite.The austenite with a lower Ni content undergoes a martensitic transformation during plastic deformation.The tensile strength of the specimen exceeds 1,100 MPa and the elongation exceeds 24%after solid solution,and further increases to 1,247 MPa and 25%after aging treatment.This enhancement is due to the TRIP effect of austenite and the precipitation of the nanoscale G-phase pinning dislocations in ferrite and martensite.
基金supported by the National Natural Science Foundation of China(Grant No.12272029).
文摘During perfusion culture,the growth of bone tissues in the scaffold was closely related to the locations of initial adhered cells and their density.In this study,the fluid mechanical responses of Voronoi-lattice scaffolds and initial adhered cells on scaffolds were quantitatively investigated.Multiphase fluid-structure interaction(FSI)model was verified by comparing with the results of Diamond scaffolds culture in the literature.Fluid mechanical responses of Voronoi-lattice scaffolds and cells were analyzed by multiphase FSI model.Regression equations were established by response surface method(RSM)to determine relationships between structural design factors of Voronoi-lattice scaffolds and fluid mechanical response parameters of scaffolds and cells.The results showed that the percentage of adhered cells and the locations of initial adhered cells obtained by multiphase FSI model of Diamond scaffolds had the same trend with that obtained by perfusion culture.Regression equations established based on RSM could well predict the fluid mechanical response parameters of Voronoi-scaffolds and cells.The multiphase FSI model closely related the densities of cells and the locations of adhered cells to bone tissue growth.The model could provide a certain theoretical basis for constructing and culturing engineered bone tissues in vitro perfusion.
基金supported by National Natural Science Foundations of China (Nos. 52307163 and 12305279)the China Postdoctoral Science Foundation (Nos. 2023M740498 and 2022M710590)Postdoctoral Fellowship Program of CPSF (No. GZC20230348)。
文摘In recent years, antibiotic pollution has become a serious threat to human health. In this study, a gas-liquid discharge plasma is developed to degrade ciprofloxacin hydrochloride in a multiphase mixed system containing inorganic and organic impurities. The discharge characteristics are analyzed by diagnosing the applied voltage and discharge current waveforms, as well as the optical emission spectra. The work investigates how degradation efficiency is affected by applied voltage, gas flow rate, treatment time, initial concentration as well as the addition of γ-Al_(2)O_(3) pellets and peanut straw. After 70 min, the degradation efficiency of ciprofloxacin hydrochloride in the multiphase mixed system reached 99.6%. Its removal efficiency increases as the initial concentration decreases and the applied voltage increases. Besides, there is still a good degradation efficiency of ciprofloxacin hydrochloride with the addition of peanut straw.The degradation mechanism of ciprofloxacin hydrochloride is investigated through the analysis of degraded intermediates and reactive species.
基金funded by the National Natural Science Foundation of China(No.51806236,No.51806239)the Fundamental Research Funds for the Central Universities(No.2015XKMS059)+1 种基金Shaanxi Postdoctoral Fund Project(No.2018BSHEDZZ56)Foundation of Key Laboratory of Thermo-Fluid Science and Engineering(Xi'an Jiaotong University),Ministry of Education(No.KLTFSE2017KF01)。
文摘The spiral-wound heat exchanger(SWHE) is the primary low-temperature heat exchanger for large-scale LNG plants due to its high-pressure resistance, compact structure, and high heat exchange efficiency. This paper studied the shell-side heat and mass transfer characteristics of vapor-liquid two-phase mixed refrigerants in an SWHE by combining a multi-component model in FLUENT software with a customized multicomponent mass transfer model. Besides, the mathematical model under the sloshing condition was obtained through mathematical derivation, and the corresponding UDF code was loaded into FLUENT as the momentum source term. The results under the sloshing conditions were compared with the relevant parameters under the steady-state condition. The shell-side heat and mass transfer characteristics of the SWHE were investigated by adjusting the component ratio and other working conditions. It was found that the sloshing conditions enhance the heat transfer performance and sometimes have insignificant effects. The sloshing condition is beneficial to reduce the flow resistance. The comprehensive performance of multi-component refrigerants has been improved and the improvement is more significant under sloshing conditions, considering both the heat transfer and pressure drop.These results will provide theoretical support for the research and design of multi-component heat and mass transfer enhancement of LNG SWHE under ocean sloshing conditions.
