This paper introduces a novel fractional-order model based on the Caputo-Fabrizio(CF)derivative for analyzing computer virus propagation in networked environments.The model partitions the computer population into four...This paper introduces a novel fractional-order model based on the Caputo-Fabrizio(CF)derivative for analyzing computer virus propagation in networked environments.The model partitions the computer population into four compartments:susceptible,latently infected,breaking-out,and antivirus-capable systems.By employing the CF derivative—which uses a nonsingular exponential kernel—the framework effectively captures memory-dependent and nonlocal characteristics intrinsic to cyber systems,aspects inadequately represented by traditional integer-order models.Under Lipschitz continuity and boundedness assumptions,the existence and uniqueness of solutions are rigorously established via fixed-point theory.We develop a tailored two-step Adams-Bashforth numerical scheme for the CF framework and prove its second-order accuracy.Extensive numerical simulations across various fractional orders reveal that memory effects significantly influence virus transmission and control dynamics;smaller fractional orders produce more pronounced memory effects,delaying both infection spread and antivirus activation.Further theoretical analysis,including Hyers-Ulam stability and sensitivity assessments,reinforces the model’s robustness and identifies key parameters governing virus dynamics.The study also extends the framework to incorporate stochastic effects through a stochastic CF formulation.These results underscore fractional-order modeling as a powerful analytical tool for developing robust and effective cybersecurity strategies.展开更多
The growing need for sustainable energy solutions,driven by rising energy shortages,environmental concerns,and the depletion of conventional energy sources,has led to a significant focus on renewable energy.Solar ener...The growing need for sustainable energy solutions,driven by rising energy shortages,environmental concerns,and the depletion of conventional energy sources,has led to a significant focus on renewable energy.Solar energy,among the various renewable sources,is particularly appealing due to its abundant availability.However,the efficiency of commercial solar photovoltaic(PV)modules is hindered by several factors,notably their conversion efficiency,which averages around 19%.This efficiency can further decline to 10%–16%due to temperature increases during peak sunlight hours.This study investigates the cooling of PV modules by applying water to their front surface through Computational fluid dynamics(CFD).The study aimed to determine the optimal conditions for cooling the PV module by analyzing the interplay between water film thickness,Reynolds number,and their effects on temperature reduction and heat transfer.The CFD analysis revealed that the most effective cooling condition occurred with a 5 mm thick water film and a Reynolds number of 10.These specific parameters were found to maximize the heat transfer and temperature reduction efficiency.This finding is crucial for the development of practical and efficient cooling systems for PV modules,potentially leading to improved performance and longevity of solar panels.Alternative cooling fluids or advanced cooling techniques that might offer even better efficiency or practical benefits.展开更多
Many fishes use undulatory fin to propel themselves in the underwater environment. These locomotor mechanisms have a popular interest to many researchers. In the present study, we perform a three-dimensional unsteady ...Many fishes use undulatory fin to propel themselves in the underwater environment. These locomotor mechanisms have a popular interest to many researchers. In the present study, we perform a three-dimensional unsteady computation of an undulatory mechanical fin that is driven by Shape Memory Alloy （SMA）. The objective of the computation is to investigate the fluid dynamics of force production associated with the undulatory mechanical fin. An unstructured, grid-based, unsteady Navier-Stokes solver with automatic adaptive remeshing is used to compute the unsteady flow around the fin through five complete cycles. The pressure distribution on fin surface is computed and integrated to provide fin forces which are decomposed into lift and thrust. The velocity field is also computed throughout the swimming cycle. Finally, a comparison is conducted to reveal the dynamics of force generation according to the kinematic parameters of the undulatory fin （amplitude, frequency and wavelength）.展开更多
To find out and improve the flow characteristics inside the intake system of cylinder head,the application of computational fluid dynamics(CFD)in the evaluation and optimization of the reconstructed intake system base...To find out and improve the flow characteristics inside the intake system of cylinder head,the application of computational fluid dynamics(CFD)in the evaluation and optimization of the reconstructed intake system based on slicing reverse method was proposed.The flow characteristics were found out through CFD,and the velocity vector field,pressure field and turbulent kinetic energy field for different valve lifts were discussed,which were in good agreement with experimental data,and the quality of reconstruction was evaluated.In order to improve its flow characteristic,an optimization plan was proposed.The results show that the flow characteristics after optimization are obviously improved.The results can provide a reference for the design and optimization of the intake system of cylinder head.展开更多
复杂地形风电场流动具有强烈的非定常现象和多尺度特征,其准确模拟是风资源精细化评估的难点。为兼顾宏观中尺度大气环流和微观非定常流动细节,该文结合中尺度气象研究与预报(weather research and forecasting,WRF)模式和微尺度计算流...复杂地形风电场流动具有强烈的非定常现象和多尺度特征,其准确模拟是风资源精细化评估的难点。为兼顾宏观中尺度大气环流和微观非定常流动细节,该文结合中尺度气象研究与预报(weather research and forecasting,WRF)模式和微尺度计算流体动力学(computational fluid dynamics,CFD)技术,构建一套WRF-CFD模式耦合的复杂地形风电场非定常仿真方法。以国际经典案例Askervein山和Bolund岛为验证对象,研究复杂地形流场中平均风速和湍流强度的分布特征,并简要分析复杂地形中风力机布置策略。结果表明,基于WRF-CFD模式的数值模拟结果与实验观测值有较好的一致性,且优于中尺度数值模拟结果,在选取的特征点位置,风速绝对误差均在2 m/s以内。结果可为风力机的设计、布局、载荷评估及风电场运行控制提供一定参考。展开更多
Chassis-by-wire technology has gained significant attention,with the scope of chassis domain control expanding from traditional two-dimensional plane motion control to encompass three-dimensional space motion control....Chassis-by-wire technology has gained significant attention,with the scope of chassis domain control expanding from traditional two-dimensional plane motion control to encompass three-dimensional space motion control.Modern chassis-by-wire systems manage an increasing number of heterogeneous chassis execution systems,including distributed drive,all-wheel drive(AWD),brake-by-wire(BBW),steer-by-wire(SBW),rear-wheel steering(RWS),active stabilizer bar(ASB)and active suspension system(ASS),greatly enhancing the controllable degrees of freedom compared to conventional chassis configurations.To advance research in chassis domain control,it is essential to understand how these heterogeneous execution systems influence vehicle dynamics.This paper focuses on the modeling and analysis of the lateral,longitudinal,and vertical chassis control and execution systems,-as well as their impact on vehicle lateral motion.Using a vehicle simulation platform,both the vehicle dynamics model and the individual dynamics models of each execution system were developed to analyze the influence of these systems on lateral dynamics.Additionally,a hierarchical control architecture was designed to control the vehicle’s lateral stability.The effectiveness of the proposed control scheme was demonstrated and validated through hardware-in-the-loop(HIL)tests and real-world vehicle testing.展开更多
The 53rd issue of Financial Innovation(FIN),Volume 11,No.5(2025),features 21 papers that can be classified into four main themes:the Special Issue on The Anomie of Artificial Intelligence(AI)in Finance:Bridging the Ga...The 53rd issue of Financial Innovation(FIN),Volume 11,No.5(2025),features 21 papers that can be classified into four main themes:the Special Issue on The Anomie of Artificial Intelligence(AI)in Finance:Bridging the Gap Between Technical Power and Human Wisdom,and Financial Markets and Investments,Economic and Policy Analysis,Corporate Governance and Related Market Dynamics.展开更多
Plate heat exchangers suffer from significant energy losses,which adversely affect the overall efficiency of thermal systems.To address this challenge,various heat transfer enhancement techniques have been investigate...Plate heat exchangers suffer from significant energy losses,which adversely affect the overall efficiency of thermal systems.To address this challenge,various heat transfer enhancement techniques have been investigated.Notably,the incorporation of surface corrugations is widely recognized as both effective and practical.Chevron corrugation is the most employed design.However,there remains a need to investigate alternative geometries that may offer superior performance.This study aims to find a novel corrugation design by conducting a comparative CFD analysis of flat,square,chevron,and cylindrical corrugated surfaces,assessing their impact on heat transfer enhancement within a plate heat exchanger.ANSYS Fluent software was used for simulation at four distinct Reynolds numbers(10,000,18,000,26,000,and 28,000),with a heat flux of 12,000 W/m^(2).A structured mesh was generated using Pointwise software.The material of the solid plates was modelled as aluminum,the fluid was modelled as water,and the flow was turbulent.To obtain a fully developed turbulent flow,a separate inlet duct was modelled,and the output velocity profile of the inlet duct was input into the plate heat exchanger.The Nusselt number(Nu)and heattransfer coefficient(h)were calculated to evaluate the performance of all surfaces.The results indicate that cylindrical corrugated surfaces exhibit higher Nusselt numbers than chevron,square,and flat plates.This higher performance is because of the generation of vortices in the middle of the cylindrical texture.Consequently,flow recirculation occurs,leading to reattachment to the mainstreamflow.This phenomenon induces increased turbulence,thereby enhancing the heat transfer efficiency.To validate the results,a grid-convergence independence test was performed for three different mesh sizes.In addition,empirical calculations were performed using the Dittus-Boelter and the Genilaski equations to validate the results of the flat-plate heat exchanger.It was concluded that the cylinder was the best corrugated surface and had a maximum heat transfer 35%higher than that of a flat plate.展开更多
The rapid advancement of technology and the increasing speed of vehicles have led to a substantial rise in energy consumption and growing concern over environmental pollution.Beyond the promotion of new energy vehicle...The rapid advancement of technology and the increasing speed of vehicles have led to a substantial rise in energy consumption and growing concern over environmental pollution.Beyond the promotion of new energy vehicles,reducing aerodynamic drag remains a critical strategy for improving energy efficiency and lowering emissions.This study investigates the influence of key geometric parameters on the aerodynamic drag of vehicles.A parametric vehicle model was developed,and computational fluid dynamics(CFD)simulations were conducted to analyse variations in the drag coefficient(C_(d))and pressure distribution across different design configurations.The results reveal that the optimal aerodynamic performance—characterized by a minimized drag coefficient—is achieved with the following parameter settings:engine hood angle(α)of 15°,windshield angle(β)of 25°,rear window angle(γ)of 40°,rear upwards tail lift angle(θ)of 10°,ground clearance(d)of 100 mm,and side edge angle(s)of 5°.These findings offer valuable guidance for the aerodynamic optimization of vehicle body design and contribute to strategies aimed at energy conservation and emission reduction in the automotive sector.展开更多
This study aims to establish an integrated sensitivity analysis framework for optimization and design of the dynamic performance of mechanical systems such as tracked vehicles,by combining the direct differentiation m...This study aims to establish an integrated sensitivity analysis framework for optimization and design of the dynamic performance of mechanical systems such as tracked vehicles,by combining the direct differentiation method(DDM)with the linear multibody system transfer matrix method(linear MSTMM).The rigid-flexible coupled multibody system dynamics model of a tracked vehicle is established using the linear MSTMM and validated through the modal test.Building upon the existing DDM-based eigenvalue sensitivity analysis method within the linear MSTMM,the DDM is embedded into it to enable programmable and efficient computation of dynamic response sensitivities for mechanical systems.The proposed approach is used to quantitatively evaluate the sensitivities of both natural vibration characteristics(e.g.,natural frequencies and mode shapes)and transient dynamic responses of the tracked vehicle with respect to system parameters,successfully identifying critical structural parameters.Compared to conventional finite difference methods,the developed methodology eliminates sensitivity to perturbation step sizes.The contributions of this work lie in establishing a unified theoretical foundation and analysis framework for guiding dynamics optimization and design of mechanical systems,and extending the applicability of the linear MSTMM to sensitivity analysis of transient dynamic responses.展开更多
基金supported and funded by the Deanship of Scientific Research at Imam Mohammad Ibn Saud Islamic University(IMSIU)(grant number IMSIU-DDRSP2601).
文摘This paper introduces a novel fractional-order model based on the Caputo-Fabrizio(CF)derivative for analyzing computer virus propagation in networked environments.The model partitions the computer population into four compartments:susceptible,latently infected,breaking-out,and antivirus-capable systems.By employing the CF derivative—which uses a nonsingular exponential kernel—the framework effectively captures memory-dependent and nonlocal characteristics intrinsic to cyber systems,aspects inadequately represented by traditional integer-order models.Under Lipschitz continuity and boundedness assumptions,the existence and uniqueness of solutions are rigorously established via fixed-point theory.We develop a tailored two-step Adams-Bashforth numerical scheme for the CF framework and prove its second-order accuracy.Extensive numerical simulations across various fractional orders reveal that memory effects significantly influence virus transmission and control dynamics;smaller fractional orders produce more pronounced memory effects,delaying both infection spread and antivirus activation.Further theoretical analysis,including Hyers-Ulam stability and sensitivity assessments,reinforces the model’s robustness and identifies key parameters governing virus dynamics.The study also extends the framework to incorporate stochastic effects through a stochastic CF formulation.These results underscore fractional-order modeling as a powerful analytical tool for developing robust and effective cybersecurity strategies.
文摘The growing need for sustainable energy solutions,driven by rising energy shortages,environmental concerns,and the depletion of conventional energy sources,has led to a significant focus on renewable energy.Solar energy,among the various renewable sources,is particularly appealing due to its abundant availability.However,the efficiency of commercial solar photovoltaic(PV)modules is hindered by several factors,notably their conversion efficiency,which averages around 19%.This efficiency can further decline to 10%–16%due to temperature increases during peak sunlight hours.This study investigates the cooling of PV modules by applying water to their front surface through Computational fluid dynamics(CFD).The study aimed to determine the optimal conditions for cooling the PV module by analyzing the interplay between water film thickness,Reynolds number,and their effects on temperature reduction and heat transfer.The CFD analysis revealed that the most effective cooling condition occurred with a 5 mm thick water film and a Reynolds number of 10.These specific parameters were found to maximize the heat transfer and temperature reduction efficiency.This finding is crucial for the development of practical and efficient cooling systems for PV modules,potentially leading to improved performance and longevity of solar panels.Alternative cooling fluids or advanced cooling techniques that might offer even better efficiency or practical benefits.
文摘Many fishes use undulatory fin to propel themselves in the underwater environment. These locomotor mechanisms have a popular interest to many researchers. In the present study, we perform a three-dimensional unsteady computation of an undulatory mechanical fin that is driven by Shape Memory Alloy （SMA）. The objective of the computation is to investigate the fluid dynamics of force production associated with the undulatory mechanical fin. An unstructured, grid-based, unsteady Navier-Stokes solver with automatic adaptive remeshing is used to compute the unsteady flow around the fin through five complete cycles. The pressure distribution on fin surface is computed and integrated to provide fin forces which are decomposed into lift and thrust. The velocity field is also computed throughout the swimming cycle. Finally, a comparison is conducted to reveal the dynamics of force generation according to the kinematic parameters of the undulatory fin （amplitude, frequency and wavelength）.
基金“Strategic Cooperation of Science and Technology between Nanchong City and Southwest Petroleum University 2018” Special Fund Project,China(Nos.18SXHZ0030,18SXHZ0054)
文摘To find out and improve the flow characteristics inside the intake system of cylinder head,the application of computational fluid dynamics(CFD)in the evaluation and optimization of the reconstructed intake system based on slicing reverse method was proposed.The flow characteristics were found out through CFD,and the velocity vector field,pressure field and turbulent kinetic energy field for different valve lifts were discussed,which were in good agreement with experimental data,and the quality of reconstruction was evaluated.In order to improve its flow characteristic,an optimization plan was proposed.The results show that the flow characteristics after optimization are obviously improved.The results can provide a reference for the design and optimization of the intake system of cylinder head.
文摘复杂地形风电场流动具有强烈的非定常现象和多尺度特征,其准确模拟是风资源精细化评估的难点。为兼顾宏观中尺度大气环流和微观非定常流动细节,该文结合中尺度气象研究与预报(weather research and forecasting,WRF)模式和微尺度计算流体动力学(computational fluid dynamics,CFD)技术,构建一套WRF-CFD模式耦合的复杂地形风电场非定常仿真方法。以国际经典案例Askervein山和Bolund岛为验证对象,研究复杂地形流场中平均风速和湍流强度的分布特征,并简要分析复杂地形中风力机布置策略。结果表明,基于WRF-CFD模式的数值模拟结果与实验观测值有较好的一致性,且优于中尺度数值模拟结果,在选取的特征点位置,风速绝对误差均在2 m/s以内。结果可为风力机的设计、布局、载荷评估及风电场运行控制提供一定参考。
基金Supported by National Nature Science Foundation of China(Grant Nos.52325212,52372394)National Key Research and Development Program of China(Grant Nos.2022YFE0117100,2021YFB2501201)+1 种基金Industry-University-Research Innovation Fund for Chinese Universities(Grand No.2024HT010)Fundamental Research Funds for the Central Universities.
文摘Chassis-by-wire technology has gained significant attention,with the scope of chassis domain control expanding from traditional two-dimensional plane motion control to encompass three-dimensional space motion control.Modern chassis-by-wire systems manage an increasing number of heterogeneous chassis execution systems,including distributed drive,all-wheel drive(AWD),brake-by-wire(BBW),steer-by-wire(SBW),rear-wheel steering(RWS),active stabilizer bar(ASB)and active suspension system(ASS),greatly enhancing the controllable degrees of freedom compared to conventional chassis configurations.To advance research in chassis domain control,it is essential to understand how these heterogeneous execution systems influence vehicle dynamics.This paper focuses on the modeling and analysis of the lateral,longitudinal,and vertical chassis control and execution systems,-as well as their impact on vehicle lateral motion.Using a vehicle simulation platform,both the vehicle dynamics model and the individual dynamics models of each execution system were developed to analyze the influence of these systems on lateral dynamics.Additionally,a hierarchical control architecture was designed to control the vehicle’s lateral stability.The effectiveness of the proposed control scheme was demonstrated and validated through hardware-in-the-loop(HIL)tests and real-world vehicle testing.
文摘The 53rd issue of Financial Innovation(FIN),Volume 11,No.5(2025),features 21 papers that can be classified into four main themes:the Special Issue on The Anomie of Artificial Intelligence(AI)in Finance:Bridging the Gap Between Technical Power and Human Wisdom,and Financial Markets and Investments,Economic and Policy Analysis,Corporate Governance and Related Market Dynamics.
文摘Plate heat exchangers suffer from significant energy losses,which adversely affect the overall efficiency of thermal systems.To address this challenge,various heat transfer enhancement techniques have been investigated.Notably,the incorporation of surface corrugations is widely recognized as both effective and practical.Chevron corrugation is the most employed design.However,there remains a need to investigate alternative geometries that may offer superior performance.This study aims to find a novel corrugation design by conducting a comparative CFD analysis of flat,square,chevron,and cylindrical corrugated surfaces,assessing their impact on heat transfer enhancement within a plate heat exchanger.ANSYS Fluent software was used for simulation at four distinct Reynolds numbers(10,000,18,000,26,000,and 28,000),with a heat flux of 12,000 W/m^(2).A structured mesh was generated using Pointwise software.The material of the solid plates was modelled as aluminum,the fluid was modelled as water,and the flow was turbulent.To obtain a fully developed turbulent flow,a separate inlet duct was modelled,and the output velocity profile of the inlet duct was input into the plate heat exchanger.The Nusselt number(Nu)and heattransfer coefficient(h)were calculated to evaluate the performance of all surfaces.The results indicate that cylindrical corrugated surfaces exhibit higher Nusselt numbers than chevron,square,and flat plates.This higher performance is because of the generation of vortices in the middle of the cylindrical texture.Consequently,flow recirculation occurs,leading to reattachment to the mainstreamflow.This phenomenon induces increased turbulence,thereby enhancing the heat transfer efficiency.To validate the results,a grid-convergence independence test was performed for three different mesh sizes.In addition,empirical calculations were performed using the Dittus-Boelter and the Genilaski equations to validate the results of the flat-plate heat exchanger.It was concluded that the cylinder was the best corrugated surface and had a maximum heat transfer 35%higher than that of a flat plate.
基金funded by the“Hundred Outstanding Talents”Support Program of Jining University,a provincial-level key project in the field of natural sciences,grant number 2023ZYRC23Jining Key R&D Program(Soft Science)Project,No.2024JNZC010Shandong Province Key Research and Development Program(Technology-Based Small and Medium-sized Enterprises Innovation Capability Improvement)Project No.2025TSGCCZZB0679.
文摘The rapid advancement of technology and the increasing speed of vehicles have led to a substantial rise in energy consumption and growing concern over environmental pollution.Beyond the promotion of new energy vehicles,reducing aerodynamic drag remains a critical strategy for improving energy efficiency and lowering emissions.This study investigates the influence of key geometric parameters on the aerodynamic drag of vehicles.A parametric vehicle model was developed,and computational fluid dynamics(CFD)simulations were conducted to analyse variations in the drag coefficient(C_(d))and pressure distribution across different design configurations.The results reveal that the optimal aerodynamic performance—characterized by a minimized drag coefficient—is achieved with the following parameter settings:engine hood angle(α)of 15°,windshield angle(β)of 25°,rear window angle(γ)of 40°,rear upwards tail lift angle(θ)of 10°,ground clearance(d)of 100 mm,and side edge angle(s)of 5°.These findings offer valuable guidance for the aerodynamic optimization of vehicle body design and contribute to strategies aimed at energy conservation and emission reduction in the automotive sector.
基金supported by the Natural Science Foundation of Jiangsu Province,China(Grant No.BK20241443)the Jiangsu Funding Program for Excellent Postdoctoral Talent(Grant No.2024ZB072)the National Natural Science Foundation of China(Grant No.92266201).
文摘This study aims to establish an integrated sensitivity analysis framework for optimization and design of the dynamic performance of mechanical systems such as tracked vehicles,by combining the direct differentiation method(DDM)with the linear multibody system transfer matrix method(linear MSTMM).The rigid-flexible coupled multibody system dynamics model of a tracked vehicle is established using the linear MSTMM and validated through the modal test.Building upon the existing DDM-based eigenvalue sensitivity analysis method within the linear MSTMM,the DDM is embedded into it to enable programmable and efficient computation of dynamic response sensitivities for mechanical systems.The proposed approach is used to quantitatively evaluate the sensitivities of both natural vibration characteristics(e.g.,natural frequencies and mode shapes)and transient dynamic responses of the tracked vehicle with respect to system parameters,successfully identifying critical structural parameters.Compared to conventional finite difference methods,the developed methodology eliminates sensitivity to perturbation step sizes.The contributions of this work lie in establishing a unified theoretical foundation and analysis framework for guiding dynamics optimization and design of mechanical systems,and extending the applicability of the linear MSTMM to sensitivity analysis of transient dynamic responses.
