期刊文献+
共找到13,015篇文章
< 1 2 250 >
每页显示 20 50 100
Dynamics of Nonlinear Rossby Waves With the Derivative-Expansion Method
1
作者 TIAN Hongxiao ZHANG Ruigang LIU Quansheng 《应用数学和力学》 北大核心 2026年第3期313-328,共16页
Nonlinear Rossby waves are used to describe typical wave phenomena in large-scale atmosphere andocean.Owing to the nonlinearity of the involved problems,the weakly nonlinear method,ie the derivative ex-pansion method,... Nonlinear Rossby waves are used to describe typical wave phenomena in large-scale atmosphere andocean.Owing to the nonlinearity of the involved problems,the weakly nonlinear method,ie the derivative ex-pansion method,was mainly used to investigate Rossby waves under the combined effects of the generalizedβ-effect and the basic flow effect.The derivative expansion method has the advantage of capturing the multi-scalecharacteristics of wave processes simultaneously.In the case where the perturbation expansion is independentof secular terms,the nonlinear equations describing the amplitude evolution of nonlinear waves were derived,such as the Korteweg-de Vries equation,the Boussinesq equation and Zakharov-Kuznetsov equation.Both quali-tative and quantitative analyses indicate that the generalizedβ-effect is the key factor inducing the evolution ofRossby solitary waves. 展开更多
关键词 planetary Rossby waves generalized beta effect derivative-expansion method nonlinear equation
在线阅读 下载PDF
Nonlinear Seismic Response of Tunnels in Longitudinally Inhomogeneous Strata Subjected to Obliquely Incident SV Waves
2
作者 Xiaole Jiang Jingqi Huang +2 位作者 Xu Zhao Wenlong Ouyang Xianghui Zhao 《Computer Modeling in Engineering & Sciences》 2026年第3期388-415,共28页
To address the complex seismic response of long tunnels longitudinally crossing heterogeneous geological formations,this study proposes a three-dimensional SV-wave oblique-incidence input method that accounts for the ... To address the complex seismic response of long tunnels longitudinally crossing heterogeneous geological formations,this study proposes a three-dimensional SV-wave oblique-incidence input method that accounts for the initial disturbance of the wave field induced by geological heterogeneity.The method transforms equivalent twodimensional free-field responses into equivalent nodal forces applied at the boundaries of a 3D numerical model.A longitudinally heterogeneous“hard-soft-hard”site and tunnel system is established,in which the surrounding rock is modeled using the Mohr-Coulomb constitutive law,while the concrete lining is described by the concrete damaged plasticity model.The deformation patterns and failure mechanisms of the site-tunnel system under SV-wave excitation are systematically investigated.The results indicate that seismic damage under SV-wave loading is mainly concentrated in the soft-rock region.Failure of the soft surrounding rock induces pronounced sliding of the overlying hard rock,and the tunnel suffers severe damage due to the combined effects of soft-rock failure and strong ground shaking.Parametric analyses further show that smaller impedance ratios,larger soft-rock widths,and larger incidence angles significantly intensify the seismic response of the tunnel.The findings of this study provide valuable insights for the seismic design of tunnels crossing longitudinally heterogeneous geological formations. 展开更多
关键词 Inhomogeneous geology SV waves tunnel earthquake time-domain wave propagation approach
在线阅读 下载PDF
Case analysis of diurnal stratospheric Rayleigh temperature and atmospheric fluctuations based on 589 nm lidar
3
作者 ZhiFang Chen ZhaoAi Yan +5 位作者 Xiong Hu WenJie Guo ZunJie Wu HaiLong Sun ShangYong Guo YongQiang Cheng 《Earth and Planetary Physics》 2026年第2期251-258,共8页
Observational analysis of the Earth’s stratospheric temperature structure and its dynamical behavior is of great significance for atmospheric dynamics research.In this paper,we present stratospheric temperatures in t... Observational analysis of the Earth’s stratospheric temperature structure and its dynamical behavior is of great significance for atmospheric dynamics research.In this paper,we present stratospheric temperatures in the range of 30–50 km above the Yinchuan observation site,retrieved from diurnal continuous Rayleigh scattering signal observation data collected by a 589 nm lidar throughout a single day.We also present observational studies of atmospheric tides and gravity wave cases.The diurnal temperature background field and perturbation field were obtained from the lidar data using the linear fitting method;these results exhibit good consistency with the temperature perturbation field extracted from ERA5.An obvious quasi-monochromatic inertial gravity wave was detected by application of a two-dimensional Fourier transform to the nighttime observation data with complete height coverage,which revealed these characteristic gravity wave parameters:a vertical wavelength of 8.53 km,a period of 8.46 h,and a downward-propagating vertical phase velocity.A nonlinear least-squares harmonic fitting method was used to extract amplitudes and phases of atmospheric diurnal and semi-diurnal tides in the 30−34 km range,where the diurnal data were relatively complete.The amplitudes increased with height,ranging from 0.6 to 2.5 K(diurnal tide)and 0.3 to 1.9 K(semi-diurnal tide),respectively.The phases showed a decreasing trend with height,indicating that the vertical phase velocity of the tides propagates downward while the energy propagates upward.These results indicate that diurnal 589 nm lidar observations data can provide important reference values for understanding the temperature structure of the stratosphere and the dynamical characteristics of atmospheric gravity waves and tides. 展开更多
关键词 STRATOSPHERE atmospheric temperature quasi-monochromatic inertial gravity wave vertical wavelength period atmospheric tidal wave
在线阅读 下载PDF
Effects of end caps of cylindrical casing on fragment velocity distribution
4
作者 Yueguang Gao Jianping Fu +3 位作者 Siyu Wu Xuke Lan Kai Ren Rui Yang 《Defence Technology(防务技术)》 2026年第3期377-394,共18页
Fragment velocity distribution is an important parameter affecting the terminal effects of warheads.The rarefaction wave,end cap,and its confinement state can significantly affect the fragmentation of the cylindrical ... Fragment velocity distribution is an important parameter affecting the terminal effects of warheads.The rarefaction wave,end cap,and its confinement state can significantly affect the fragmentation of the cylindrical charge casing.Most of the existing studies have performed experiments and simulations considering the rarefaction wave and unfixed end caps;research on fixed end caps and sufficient theoretical explanations are limited.In this work,the effects of rarefaction waves,end caps,and their fixed states,on the fragment velocity distribution,were studied via experimentation and simulation,and reasonable theoretical explanations were provided.The results show that the rarefaction wave and end caps affect the fragment velocity by changing the pressure states of the detonation products.At the initiation end,the fragment velocities of casings with unfixed initiation ends are 33.3%(300 m/s)greater than that of casings without end caps,because of the weakening of the attenuation effect of the rarefaction wave.The fragment velocities of the casings with fixed initiation ends are 8.3%(100 m/s)greater than that of casings with unfixed initiation ends.At the non-initiation end,the fragment velocities are 24.8%(297 m/s)greater than that of a casing without end caps,and the reflecting shock wave generated by the fixed non-initiation end increases the fragment velocity by 7.3%(113 m/s),compared to the theoretical velocity.This work provides a basis for the structural design and analysis of the terminal effects of warheads. 展开更多
关键词 Fragment velocity Numerical simulation X-ray radiography Axial rarefaction waves Reflect shock wave Cylindrical casing
在线阅读 下载PDF
Residual Symmetry Reductions and Painlevé Solitons
5
作者 Yan Li Ya-Rong Xia +1 位作者 Ruo-Xia Yao Sen-Yue Lou 《Chinese Physics Letters》 2026年第1期3-8,共6页
This letter introduces the novel concept of Painlevé solitons—waves arising from the interaction between Painlevé waves and solitons in integrable systems.Painlevé solitons can also be viewed as solito... This letter introduces the novel concept of Painlevé solitons—waves arising from the interaction between Painlevé waves and solitons in integrable systems.Painlevé solitons can also be viewed as solitons propagating against a Painlevé wave background,in analogy to the established notion of elliptic solitons,which refers to solitons on an elliptic wave background.By employing a novel symmetry decomposition method aided by nonlocal residual symmetries,we explicitly construct (extended) Painlevé Ⅱ solitons for the Korteweg-de Vries equation and (extended) Painlevé Ⅳ solitons for the Boussinesq equation. 展开更多
关键词 integrable systems Painlev solitons elliptic solitonswhich residual symmetry reductions symmetry decomposition method painlev waves painlev solitons waves
原文传递
Analytical solution for longitudinal responses of tunnels under combined effects of seismic waves and strike-slip faulting
6
作者 Jie Tang Manchao He +2 位作者 Yafei Qiao Hanbing Bian Chun Zhu 《Journal of Rock Mechanics and Geotechnical Engineering》 2026年第2期1266-1289,共24页
Strong seismic excitation and fault dislocation are likely to occur simultaneously in high-intensity seismic zones,causing severe damage to tunnels crossing active fault zones.This paper aims to develop a novel analyt... Strong seismic excitation and fault dislocation are likely to occur simultaneously in high-intensity seismic zones,causing severe damage to tunnels crossing active fault zones.This paper aims to develop a novel analytical solution to determine the longitudinal mechanical responses of tunnels subjected to the combined effects of seismic waves and strike-slip faulting.Adopting the elastic springbeam model,the seismic waves are modelled as shear horizontal(SH)waves and the fault dislocation follows an S-shaped pattern;the superposition principle for free-fielddisplacements caused by both effects is assumed.In addition,the transmission and reflectionof seismic waves at the fault-rock geological interface and the tangential contact conditions at the tunnel-rock interface are considered.The analytical model is validated against numerical simulations,confirmingits accuracy in calculating tunnel responses.Moreover,a parametric study is conducted to evaluate the impact of key factors,including fault displacement,fault zone width,fault dip angle,earthquake frequency,rock conditions,tunnel lining stiffness,and tangential contact conditions,on tunnel responses.Compared with each effect alone,the combined effects of seismic waves and strike-slip faulting significantlychange the tunnel deformation and internal forces,leading to increased tunnel responses,especially within the fault zone and near the fault-rock interfaces.Depending on specificparameters,tunnel responses can be classifiedinto seismic-dominated,faulting-dominated,and seismic-faulting coupled responses on the basis of the relative contributions of each effect.The proposed analytical solution can be applied to quickly predict the longitudinal mechanical behaviour of tunnels under such combined effects in engineering applications. 展开更多
关键词 Strike-slip faulting Longitudinal tunnel response Analytical solution Seismic waves Wave transmissions and reflections
在线阅读 下载PDF
Characteristics and mechanisms for a new damage region near the loading side of polycrystalline aluminum with helium bubbles under strongly decaying shock waves
7
作者 Tingting Zhou Fuqi Zhao +1 位作者 Anmin He Pei Wang 《Matter and Radiation at Extremes》 2026年第1期81-92,共12页
The damage evolution of polycrystalline Al with helium(He)bubbles under strongly decaying shock waves is studied by molecular dynamics simulations.A new damage region is observed near the loading side of the sample,an... The damage evolution of polycrystalline Al with helium(He)bubbles under strongly decaying shock waves is studied by molecular dynamics simulations.A new damage region is observed near the loading side of the sample,and the evolution characteristics and underlying mechanisms are elucidated.The development of damage in the new damage region begins after complete unloading of the incident shock wave and is further enhanced when the tensile stress arrives later.The damage evolution is completely controlled by the expansion-merging of He bubbles,without nucleation–growth of voids.This new damage region can be divided into two sections,each of which exhibits a unique dominant mechanism.The damage in the section closer to the loading side is due to the reverse velocity gradient formed after complete unloading of the incident shock wave,depending on the rate of decrease and the amplitude of the initial peak pressure.A high initial peak pressure that can lead to melting of material near the loading side is a necessary condition for the formation of the new damage region,since a significant reverse velocity gradient can only be established if melting occurs.The dominant mechanism in the section distant from the loading side is the action of tensile stress,associated with the profile of the incident shock wave upon reaching the free surface,which determines the material phase near the free surface.Moreover,the presence of He bubbles is another critical factor for formation of the new damage region,which does not occur in pure Al samples. 展开更多
关键词 shock wave polycrystalline aluminum strongly decaying shock waves helium bubbles molecular dynamics simulationsa molecular dynamics simulations tensile stress damage evolution
在线阅读 下载PDF
Quasibound states of massless spin particles in Schwarzschild equivalent mediums
8
作者 Li-Qin Mi Dandan Li Zhong-Heng Li 《Communications in Theoretical Physics》 2026年第2期78-87,共10页
We show that in Schwarzschild equivalent mediums,the massless spin particles obey the same dynamical equation,from which we obtain remarkably simple formulae for the frequencies of the quasibound states.We find that t... We show that in Schwarzschild equivalent mediums,the massless spin particles obey the same dynamical equation,from which we obtain remarkably simple formulae for the frequencies of the quasibound states.We find that the quasibound frequencies of different bosons can be identical at the same quantum number l,and the same is true of different fermions,but a quasibound frequency for bosons can never equal a quasibound frequency for fermions.These results mean that in Schwarzschild equivalent mediums with the quasibound-state boundary conditions,characteristics of electromagnetic waves are the same as those for all the massless bosonic waves,thereby allowing electromagnetic waves to simulate gravitational waves.Our predictions can be tested in future experiments,building upon the successful preparation of Schwarzschild equivalent mediums. 展开更多
关键词 quasibound state theory of analogical experiment Schwarzschild equivalent medium gravitational wave electromagnetic wave massless spin particle
原文传递
Progress in shock wave diagnostic technology based on velocity interferometers for laser inertial confinement fusion
9
作者 Feng Wang Yulong Li +5 位作者 Zanyang Guan Xiaoshi Peng Xiangming Liu Dong Yang Jiamin Yang Zongqing Zhao 《Matter and Radiation at Extremes》 2026年第2期1-13,共13页
Laser-driven inertial confinement fusion(ICF)is an important experimental platform for high-energy-density physics research under extreme conditions.In ICF research,high-quality shock waves are key to fusion energy re... Laser-driven inertial confinement fusion(ICF)is an important experimental platform for high-energy-density physics research under extreme conditions.In ICF research,high-quality shock waves are key to fusion energy release.The velocity interferometer system for any reflector(VISAR)is the most important diagnostic technique for measuring quantities such as shock wave and particle velocities with high precision and high spatiotemporal resolution.This paper provides a detailed introduction to the various configurations of VISAR on 10 and 100 kJ-level laser facilities in China,including Line VISAR,Dual-Axis VISAR,Wide-Angle VISAR,and Compressed Ultrafast Photography-VISAR.Recent advances and applications of VISAR diagnostics at these laser facilities are presented,and the future trend of development of high-spatiotemporal-resolution velocity diagnostic technology is described. 展开更多
关键词 laser inertial confinement fusion high energy density physics velocity interferometer system particle velocities velocity interferometer diagnostic technique shock wave diagnostic technology shock waves
在线阅读 下载PDF
Blasting effects of cross-fault deep-buried excavation on adjacent existing tunnel stability
10
作者 Shaobo Chai Lianzeng Chai +3 位作者 Chao Meng Kai Liu Lang Song Shaojie Zheng 《Deep Underground Science and Engineering》 2026年第1期66-80,共15页
The vibration caused by blasting excavation of rock mass frequently poses a threat to the stability of adjacent tunnels.Previous research is limited by the simplification of a rock mass as a homogeneous elastic medium... The vibration caused by blasting excavation of rock mass frequently poses a threat to the stability of adjacent tunnels.Previous research is limited by the simplification of a rock mass as a homogeneous elastic medium,without considering the wave attenuation caused by viscoelasticity and wave separation induced by rock discontinuities,as well as plane waves while neglecting geometric attenuation of near-field nonplane blast waves.This paper establishes a theoretical model of cylindrical P-wave propagation across a fault to an adjacent existing tunnel.Based on the time-domain recursive method,vibration equations and peak particle velocity on the adjacent existing tunnel wall caused by a cylindrical wave passing through a fault are derived.The rock mass and fault are assumed to satisfy Kelvin viscoelastic bodies,and contact interfaces between fault and rock mass follow a nonlinear hyperbolic deformation model in the normal direction and a linear model in the tangential direction.The results show that tunnel vibration caused by the blast cylindrical P-wave is primarily induced by transmitted P-waves.With the increase of the fault dip angle,vibration on the upper side of the adjacent existing tunnel gradually decreases,while vibration on the lower side increases.The closer the vibration to the upper and lower sides,the stronger the shear effect on the tunnel wall,and the closer the vibration to the middle,the stronger the pressure effect on the tunnel wall.Larger fault thickness and higher initial blast wave frequency result in weaker vibration of the adjacent tunnel.The deeper the burial depth,the stronger the vibration of the adjacent tunnel wall.Findings of this study provide insight into the dynamic response of rock construction and safety evaluation in engineering service. 展开更多
关键词 deep rock mass tunnel vibration cylindrical blast wave stress wave propagation peak particle velocity(PPV) viscoelasticity of rock mass
原文传递
Asian Monsoon Climate Prediction
11
作者 Chih-Pei CHANG 《Advances in Atmospheric Sciences》 2026年第5期1092-1094,共3页
Since Blanford(1884)first linked Himalayan snowfall to subsequent Indian summer monsoon(ISM)rainfall,the potential for long-range forecasting has been recognized.Key advances followed:discovery of the Southern Oscilla... Since Blanford(1884)first linked Himalayan snowfall to subsequent Indian summer monsoon(ISM)rainfall,the potential for long-range forecasting has been recognized.Key advances followed:discovery of the Southern Oscillation(Walker,1925;Walker and Bliss,1932);identification of the Pacific-North American pattern(Wallace and Gutzler,1981);and Bjerknes’(1969)seminal study of ENSO as a predictable climate driver.Foundational theory—including equatorial wave dynamics(Matsuno,1966;Webster,1972;Gill,1980). 展开更多
关键词 pacific north american pattern equatorial wave dynamics ENSO southern oscillation walker walker equatorial wave dynamics matsuno webster gill asian monsoon southern oscillation
在线阅读 下载PDF
Development of Wave Water Simulator for Path Planning of Autonomous Robots in Constrained Environments
12
作者 Hui Chen Mohammed A.H.Ali +6 位作者 Bushroa Abd Razak Zhenya Wang Yusoff Nukman Shikai Zhang Zhiwei Huang Ligang Yao Mohammad Alkhedher 《Computers, Materials & Continua》 2026年第4期2357-2385,共29页
Most existing path planning approaches rely on discrete expansions or localized heuristics that can lead to extended re-planning,inefficient detours,and limited adaptability to complex obstacle distributions.These iss... Most existing path planning approaches rely on discrete expansions or localized heuristics that can lead to extended re-planning,inefficient detours,and limited adaptability to complex obstacle distributions.These issues are particularly pronounced when navigating cluttered or large-scale environments that demand both global coverage and smooth trajectory generation.To address these challenges,this paper proposes a Wave Water Simulator(WWS)algorithm,leveraging a physically motivated wave equation to achieve inherently smooth,globally consistent path planning.In WWS,wavefront expansions naturally identify safe corridors while seamlessly avoiding local minima,and selective corridor focusing reduces computational overhead in large or dense maps.Comprehensive simulations and real-world validations-encompassing both indoor and outdoor scenarios-demonstrate that WWS reduces path length by 2%-13%compared to conventional methods,while preserving gentle curvature and robust obstacle clearance.Furthermore,WWS requires minimal parameter tuning across diverse domains,underscoring its broad applicability to warehouse robotics,field operations,and autonomous service vehicles.These findings confirm that the proposed wave-based framework not only bridges the gap between local heuristics and global coverage but also sets a promising direction for future extensions toward dynamic obstacle scenarios and multi-agent coordination. 展开更多
关键词 PDE-based wave propagation robot path planning obstacle avoidance wave water simulator laser simulator(LS)and generalized laser simulator(GLS) A*algorithm
在线阅读 下载PDF
Enhanced electromagnetic wave absorption in biochar/yttrium iron garnet hybrid composites for electromagnetic interference shielding applications
13
作者 Ozgur Yasin Keskin 《International Journal of Minerals,Metallurgy and Materials》 2026年第1期335-346,共12页
Biochar and biochar composites are versatile materials that can be used in many applications.In this study,biochar was prepared from sawdust and combined with the yttrium iron garnet(YIG)nanocrystal to investigate the... Biochar and biochar composites are versatile materials that can be used in many applications.In this study,biochar was prepared from sawdust and combined with the yttrium iron garnet(YIG)nanocrystal to investigate the shielding effectiveness of the composite structure.Firstly,the effect of the pyrolysis temperature on the shielding effectiveness of biochar was investigated.Secondly,biochars combined with YIG nanocrystals with different contents and shielding effectiveness of the composites were investigated.The electromagnetic effectiveness of the samples was investigated within the X band(8-12 GHz).The findings indicate that biochar demonstrates enhanced absorption properties with elevated pyrolysis temperatures.Biochars demonstrated an approximate 40 d B shielding effectiveness,while YIG exhibited approximately 7 d B,corresponding to absorption at 8 GHz.However,the combination of biochar and YIG exhibited exceptional absorption,reaching 67.12 d B at 8 GHz. 展开更多
关键词 BIOCHAR electromagnetic shielding electromagnetic wave absorption COMPOSITE
在线阅读 下载PDF
An analytical study for detonation wave boundary layer interactions under reflections
14
作者 Hao YAN Xin HAN +2 位作者 Haochen XIONG Chongguang SHI Yancheng YOU 《Chinese Journal of Aeronautics》 2026年第2期178-201,共24页
Numerical simulations and theoretical models are developed in this paper for the Detonation-Wave/Boundary-Layer Interactions(DWBLIs)under reflections.Transient flow fields demonstrate the highly non-stationarity of th... Numerical simulations and theoretical models are developed in this paper for the Detonation-Wave/Boundary-Layer Interactions(DWBLIs)under reflections.Transient flow fields demonstrate the highly non-stationarity of the DWBLIs when Mach Reflection(MR)occur,and subsequent analyses show that the subsonic region introduced by the boundary layer exacerbates the instability.Further quantitative analyses show that viscosity has little effect on propulsive performance and the separation wave can be considered as an oblique detonation wave.Influence parameters to DWBLIs such as combustion chamber height,incoming Mach number,equivalence ratio,and inlet channel length are categorized and studied.Besides simulations,theoretical analytical modeling is established for Regular Reflection(RR)and MR of DWBLIs.Multiple formulas for the separation zone length are obtained according to the mass conservation under different transformation type between inviscid and viscid reflections.Comparison with the numerical simulations verifies the validity of the model and it can be further generalized to the curved DWBLIs.The developed model makes the theoretical solution process of DWBLIs possible and provides the key foundation for further analysis and solution. 展开更多
关键词 Boundary layer interaction Detonation wave Hypersonic flow REFLECTION VISCOSITY
原文传递
Hotspot evolution and shock-induced reaction mechanism in aluminum explosives
15
作者 Zhiqiang Hu Rui Liu +1 位作者 Jianli Shao Pengwan Chen 《Defence Technology(防务技术)》 2026年第3期71-84,共14页
Aluminum nanoparticles,owing to their high energy density and excellent reactivity,are widely used to enhance the energy release efficiency of explosives.In this study,reactive molecular dynamics simulations were empl... Aluminum nanoparticles,owing to their high energy density and excellent reactivity,are widely used to enhance the energy release efficiency of explosives.In this study,reactive molecular dynamics simulations were employed to systematically investigate the hotspot evolution and reaction kinetics of aluminum nanoparticles under shock loading.The results show that hotspots predominantly form and evolve along the oxide layer interface,exhibiting a typical"hot shell-cold core"structure.A thicker oxide layer significantly delays the heating and reaction initiation of the aluminum core,with reversible crystal structure transformations observed inside the core.Larger particles facilitate heat accumulation and promote sustained reactions.As the oxide layer thickness increases,the reaction mechanism of aluminum nanoparticles transitions from melting-diffusion and micro-explosion oxidation to an oxidation-diffusion dominated process.A dense nitrogen-containing reaction layer forms on the surface,which suppresses the later-stage reaction.A nonlinear reaction kinetics model based on bond statistics reveals that particles with a thin oxide layer exhibit rapid reaction saturation and are insensitive to shock velocity.Particles with intermediate oxide thickness exhibit a reaction behavior that gradually slows down over time,while those with a thick oxide layer can exhibit accelerated reactions under high-velocity shocks due to enhanced diffusion.Small particles show significantly increased reaction rates at high velocities,whereas large particles tend to slow down due to the thickening of the surface reaction layer.The oxide layer thickness,particle size,and shock velocity exhibit complex competitive and synergistic effects that jointly regulate the initiation,rate,and evolution of aluminum nanoparticle reactions. 展开更多
关键词 Aluminum nanoparticle Shock wave Molecular dynamics HOTSPOT Chemical reaction
在线阅读 下载PDF
Convection Initiation over Mountain Slopes in North China:Roles of Upslope Winds and Orographic Waves
16
作者 Hongpei YANG Yu DU +1 位作者 Zijian CHEN Xiaoyu GAO 《Advances in Atmospheric Sciences》 2026年第5期889-906,共18页
Using high-resolution observations,mesoscale simulations,and idealized experiments,this study investigates the mechanisms governing an episode of orographic convection initiation(CI)during the North China Heavy Rainfa... Using high-resolution observations,mesoscale simulations,and idealized experiments,this study investigates the mechanisms governing an episode of orographic convection initiation(CI)during the North China Heavy Rainfall Experiment.On 4 August 2024,repeated CI occurred over the eastern slopes of the Taihang Mountains in the late afternoon,subsequently enhancing an upstream downhill convective storm.Wind profiler radar data and dense automatic weather stations reveal that CI was supported by strengthening southeasterly upslope winds.These winds primarily resulted from the migration of the mountain-plain solenoid and the mountainward-propagating outflow from a convective cold pool over the plain,with sensitivity experiments showing the latter contributed roughly 22%of the wind strength.The upslope flows gradually transported unstable air from the plain to the slope,fostering CI.Mesoscale simulations further highlight the key role of orographic waves near the mountain ridge,which generated strong downslope winds.The near-surface convergence between downslope and upslope flows,combined with wave-induced divergence aloft,produced deep ascent over the slope.Removing mountain ridges weakened wave strength and reduced downslope wind speeds by~8 m s^(-1).Without orographic heating in the idealized simulation(i.e.,no mountain-plain solenoid),only strong wave descent occurred below 2km,inhibiting CI.These findings underscore the critical interplay among plain convection,orographic waves,and the mountain-plain solenoid,offering new insight into the processes controlling orographic CI in North China. 展开更多
关键词 convection initiation mountain-plain solenoid orographic waves cold pools topographic convection
在线阅读 下载PDF
Load of the Small-Scale Vertical Cylinder in a Wave-Current Field
17
作者 Mingjie Li Binbin Zhao Wengyang Duan 《哈尔滨工程大学学报(英文版)》 2026年第1期82-94,共13页
Studies of wave-current interactions are vital for the safe design of structures.Regular waves in the presence of uniform,linear shear,and quadratic shear currents are explored by the High-Level Green-Naghdi model in ... Studies of wave-current interactions are vital for the safe design of structures.Regular waves in the presence of uniform,linear shear,and quadratic shear currents are explored by the High-Level Green-Naghdi model in this paper.The five-point central difference method is used for spatial discretization,and the fourth-order Adams predictor-corrector scheme is employed for marching in time.The domain-decomposition method is applied for the wave-current generation and absorption.The effects of currents on the wave profile and velocity field are examined under two conditions:the same velocity of currents at the still-water level and the constant flow volume of currents.Wave profiles and velocity fields demonstrate substantial differences in three types of currents owing to the diverse vertical distribution of current velocity and vorticity.Then,loads on small-scale vertical cylinders subjected to regular waves and three types of background currents with the same flow volume are investigated.The maximum load intensity and load fluctuation amplitude in uniform,linear shear,and quadratic shear currents increase sequentially.The stretched superposition method overestimates the maximum load intensity and load fluctuation amplitude in opposing currents and underestimates these values in following currents.The stretched superposition method obtains a poor approximation for strong nonlinear waves,particularly in the case of the opposing quadratic shear current. 展开更多
关键词 Wave-current interaction Cylinder load HLGN model Morison equation Regular waves
在线阅读 下载PDF
Influence of Distinct Intraseasonal Oscillation Intensities on Regional Persistent Extreme Precipitation Events over South China
18
作者 Wei LU Yao HA +5 位作者 Yimin ZHU Haixia DAI Yijia HU Yudi LIU Xiangrong YANG Zhong ZHONG 《Advances in Atmospheric Sciences》 2026年第5期1000-1018,I0017-I0023,共26页
This study investigated the characteristics and mechanisms of summer regional persistent extreme precipitation events(RPEPEs)over South China(SC)modulated by distinct intensity regimes of 10-30-day intraseasonal oscil... This study investigated the characteristics and mechanisms of summer regional persistent extreme precipitation events(RPEPEs)over South China(SC)modulated by distinct intensity regimes of 10-30-day intraseasonal oscillation(ISO).Diagnostic analyses revealed that the spatiotemporal evolution of RPEPEs exhibits robust phase-locking with the 10-30-day intraseasonal precipitation.By classifying RPEPEs into strong-ISO(SRPEPE)and weak-ISO(WRPEPE)composites based on the amplitude of 10-30-day filtered precipitation,we demonstrate a 14.6%enhancement in peak precipitation intensity during SRPEPEs compared to WRPEPEs.These distinct precipitation regimes are governed by fundamentally different Rossby wave teleconnection patterns over Eurasia.During SRPEPEs,a robust southeastward-propagating 10-30-day Rossby wave train originating from the Barents Sea traverses midlatitude Eurasia,effectively perturbing the northwestern Pacific upper-level circulation and establishing a favorable dynamic environment over SC.In contrast,WRPEPEs are associated with weaker eastward-propagating wave trains constrained along the subtropical jet stream.The horizontal convergence of background moisture driven by 10-30-day winds significantly amplifies lower-tropospheric humidity during SRPEPEs.The thermal advection of background temperature by 10-30-day geostrophic winds enhances baroclinic instability and vertical motion,intensifying precipitation under these moisture conditions. 展开更多
关键词 South China extreme precipitation intraseasonal oscillation Rossby wave
在线阅读 下载PDF
Airblast waves and noises induced by tunnel delay blasting:Field measurement and tempo-spatial analysis
19
作者 Xianshun Zhou Xuemin Zhang +3 位作者 Jianbo Fei Lichuan Wang Muhammad Irslan Khalid Xiangsheng Chen 《Journal of Rock Mechanics and Geotechnical Engineering》 2026年第2期1290-1305,共16页
Residents living near drill-and-blast tunnels often experience disturbances from blasting operations.This motivates us to investigate the characteristics of airblasts and resulting noise through on-site monitoring at ... Residents living near drill-and-blast tunnels often experience disturbances from blasting operations.This motivates us to investigate the characteristics of airblasts and resulting noise through on-site monitoring at three tunnels.The research focuses on both the temporal evolution and spatial propagation of airblasts.Temporal analysis,including peak overpressure(POp),positive duration(PD),and Fourier main frequency(MF),emphasizes the relationship between airblast characteristics,blasting delays,and rock grade.It shows that airblast bandwidths are typically in the range of 3e200 Hz,with noise levels exceeding 130 dB,which is comparable to jet engines and rocket launch.Spatial propagation analysis reveals the impact of tunnel space on airblast propagation.Although POp and PD typically decrease with distance inside the tunnel,wave superposition can cause increased overpressure and prolonged durations at far-field distances(above 60 m kg^(-1/3)).Outside the tunnel,sound radiation was influenced by azimuth and was basically determined by sound power d an often-overlooked factor.To address the anisotropic propagation of airblasts,a predictive model was proposed for external noise levels,considering variables like distance,azimuth angle,initial sound power,and wave expansion.Validated by tests,this model successfully unifies data from three studies,helping to explain and predict airblast disturbances near tunnels. 展开更多
关键词 Drill-and-blast tunnel Airblast waves Blasting noise Sound attenuation
在线阅读 下载PDF
Vertical Structure and Energy Transfer of Stationary Planetary Waves in Different Prescribed Atmospheric Stratifications
20
作者 Wenqi ZHANG Lin WANG 《Advances in Atmospheric Sciences》 2026年第1期233-246,共14页
This study investigates the relationship between atmospheric stratification (i.e., static stability given by N^(2)) and the vertical energy transfer of stationary planetary waves, and further illustrates the underlyin... This study investigates the relationship between atmospheric stratification (i.e., static stability given by N^(2)) and the vertical energy transfer of stationary planetary waves, and further illustrates the underlying physical mechanism. Specifically, for the simplified case of constant stratospheric N^(2), the refractive index square of planetary waves has a theoretical tendency to increase first and then decrease with an increased N^(2), whereas the group velocity weakens. Mechanistically, this behavior can be understood as an intensified suppression of vertical isentropic surface displacement caused by meridional heat transport of planetary waves under strong N^(2) conditions. Observational analysis corroborates this finding, demonstrating a reduction in the vertical-propagation velocity of waves with increased N^(2). A linear, quasi- geostrophic, mid-latitude beta-plane model with a constant background westerly wind and a prescribed N^(2) applicable to the stratosphere is used to obtain analytic solutions. In this model, the planetary waves are initiated by steady energy influx from the lower boundary. The analysis indicates that under strong N^(2) conditions, the amplitude of planetary waves can be sufficiently increased by the effective energy convergence due to the slowing vertical energy transfer, resulting in a streamfunction response in this model that contains more energy. For N^(2) with a quasi-linear vertical variation, the results bear a resemblance to the constant case, except that the wave amplitude and oscillating frequency show some vertical variations. 展开更多
关键词 planetary waves vertical propagation atmospheric stratification stratospheric circulation group velocity
在线阅读 下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部