The Hydrodynamic Ram(HRAM)effect occurs when a high kinetic energy projectile penetrates a fluid filled area,e.g.,a liquid filled tank.The projectile transfers its momentum and kinetic energy to the fluid,what causes ...The Hydrodynamic Ram(HRAM)effect occurs when a high kinetic energy projectile penetrates a fluid filled area,e.g.,a liquid filled tank.The projectile transfers its momentum and kinetic energy to the fluid,what causes a sudden,local pressure rise,further expanding as primary shock wave in the fluid and developing a cavity.It is possible that the entire tank ruptures due to the loads transferred through the fluid to its surrounding structure.In the past decades,additionally to experimental investigations,HRAM has been studied using various computational approaches particularly focusing on the description of the Fluid-Structure Interaction(FSI).This article reviews the published experimental,analytical and numerical results and delivers a chronological overview since the end of World War II.Furthermore,HRAM mitigation measures are highlighted,which have been developed with the experimental,analytical and numerical toolboxes matured over the past 80 years.展开更多
For completing the hydrodynamics software development and the engineering application research on the amphibious vehicle systems, hydrodynamic modeling theory of the amphibious vehicle systems is elaborated, which inc...For completing the hydrodynamics software development and the engineering application research on the amphibious vehicle systems, hydrodynamic modeling theory of the amphibious vehicle systems is elaborated, which includes to build up the dynamic system model of amphibious vehicle motion on water, gun tracking-aiming-firing, bullet hit and armored check-target, gunner operating control, and the simulation computed model of time domain for random sea wave.展开更多
Energetic Semiconductor bridge(ESCB)based on reactive multilayered films(RMFs)has a promising application in the miniature and intelligence of initiator and pyrotechnics device.Understanding the ignition enhancement m...Energetic Semiconductor bridge(ESCB)based on reactive multilayered films(RMFs)has a promising application in the miniature and intelligence of initiator and pyrotechnics device.Understanding the ignition enhancement mechanism of RMFs on semiconductor bridge(SCB)during the ignition process is crucial for the engineering and practical application of advanced initiator and pyrotechnics devices.In this study,a one-dimensional(1D)gas-solid two-phase flow ignition model was established to study the ignition process of ESCB to charge particles based on the reactivity of Al/MoO_(3) RMFs.In order to fully consider the coupled exothermic between the RMFs and the SCB plasma during the ignition process,the heat release of chemical reaction in RMFs was used as an internal heat source in this model.It is found that the exothermal reaction in RMFs improved the ignition performance of SCB.In the process of plasma rapid condensation with heat release,the product of RMFs enhanced the heat transfer process between the gas phase and the solid charge particle,which accelerated the expansion of hot plasma,and heated the solid charge particle as well as gas phase region with low temperature.In addition,it made up for pressure loss in the gas phase.During the plasma dissipation process,the exothermal chemical reaction in RMFs acted as the main heating source to heat the charge particle,making the surface temperature of the charge particle,gas pressure,and gas temperature rise continuously.This result may yield significant advantages in providing a universal ignition model for miniaturized ignition devices.展开更多
针对声学多普勒剖面流速仪(acoustic Doppler current profilers,简称ADCP)波浪三要素(波向、波高和波周期)计量校准技术难题,提出了造波水槽和水下实验平台的计量检测方法。首先,设计波向、波高和波周期计量标准器;然后,以美国TRDI公司...针对声学多普勒剖面流速仪(acoustic Doppler current profilers,简称ADCP)波浪三要素(波向、波高和波周期)计量校准技术难题,提出了造波水槽和水下实验平台的计量检测方法。首先,设计波向、波高和波周期计量标准器;然后,以美国TRDI公司V20型和挪威Nortek仪器为例,开展ADCP波浪参数水动力环境计量校准实验研究。实验结果表明,波高、波周期和波向数据最大示值误差分别为-0.09 m,0.6 s和4°,满足国家相关技术标准要求。波高扩展不确定度为0.04 m,依据计量学理论,认为本校准方法可行。本研究成果对ADCP波浪参数计量校准工作具有一定指导意义。展开更多
全球气候变化导致极端降雨发生频率显著增加,暴雨中心演变更加多样化,迫切需要揭示暴雨中心演变对延河流域洪水过程的影响。通过显卡加速的地表水及其伴随输移过程模型(GPU accelerated surface water flow and associated transport mo...全球气候变化导致极端降雨发生频率显著增加,暴雨中心演变更加多样化,迫切需要揭示暴雨中心演变对延河流域洪水过程的影响。通过显卡加速的地表水及其伴随输移过程模型(GPU accelerated surface water flow and associated transport model,GAST)和暴雨管理模型(storm water management model,SWMM)产流模块,模拟不同暴雨中心条件下的延河流域(河庄坪镇−姚店镇)洪水过程,分析延河流域洪水过程的变化。结果表明:当遭遇百年一遇洪水时,相对于均匀降雨,暴雨中心在水库上游时,水库可以充分发挥其调蓄功能,受灾区位数量削减率达到78%,最大水深削减率为56%;暴雨中心在水库下游时,水库的调节能力受限,受灾区位数量削减率仅为22%,最大水深削减17%;洪水淹没风险从大到小依次为现状条件下的均匀降雨、“上拦”方案实施后的均匀降雨、实施“上拦”方案下的暴雨中心在水库下游、实施“上拦”方案下的暴雨中心在水库上游。研究结果有助于量化暴雨中心演变对延河流域洪水过程的影响,指导延河流域防洪工程体系建设,从而提升延安中心城区的防灾韧性。展开更多
文摘The Hydrodynamic Ram(HRAM)effect occurs when a high kinetic energy projectile penetrates a fluid filled area,e.g.,a liquid filled tank.The projectile transfers its momentum and kinetic energy to the fluid,what causes a sudden,local pressure rise,further expanding as primary shock wave in the fluid and developing a cavity.It is possible that the entire tank ruptures due to the loads transferred through the fluid to its surrounding structure.In the past decades,additionally to experimental investigations,HRAM has been studied using various computational approaches particularly focusing on the description of the Fluid-Structure Interaction(FSI).This article reviews the published experimental,analytical and numerical results and delivers a chronological overview since the end of World War II.Furthermore,HRAM mitigation measures are highlighted,which have been developed with the experimental,analytical and numerical toolboxes matured over the past 80 years.
文摘For completing the hydrodynamics software development and the engineering application research on the amphibious vehicle systems, hydrodynamic modeling theory of the amphibious vehicle systems is elaborated, which includes to build up the dynamic system model of amphibious vehicle motion on water, gun tracking-aiming-firing, bullet hit and armored check-target, gunner operating control, and the simulation computed model of time domain for random sea wave.
基金supported by the National Natural Science Foundation of China(Grant Nos.22275092,52102107 and 52372084)the Fundamental Research Funds for the Central Universities(Grant No.30923010920)。
文摘Energetic Semiconductor bridge(ESCB)based on reactive multilayered films(RMFs)has a promising application in the miniature and intelligence of initiator and pyrotechnics device.Understanding the ignition enhancement mechanism of RMFs on semiconductor bridge(SCB)during the ignition process is crucial for the engineering and practical application of advanced initiator and pyrotechnics devices.In this study,a one-dimensional(1D)gas-solid two-phase flow ignition model was established to study the ignition process of ESCB to charge particles based on the reactivity of Al/MoO_(3) RMFs.In order to fully consider the coupled exothermic between the RMFs and the SCB plasma during the ignition process,the heat release of chemical reaction in RMFs was used as an internal heat source in this model.It is found that the exothermal reaction in RMFs improved the ignition performance of SCB.In the process of plasma rapid condensation with heat release,the product of RMFs enhanced the heat transfer process between the gas phase and the solid charge particle,which accelerated the expansion of hot plasma,and heated the solid charge particle as well as gas phase region with low temperature.In addition,it made up for pressure loss in the gas phase.During the plasma dissipation process,the exothermal chemical reaction in RMFs acted as the main heating source to heat the charge particle,making the surface temperature of the charge particle,gas pressure,and gas temperature rise continuously.This result may yield significant advantages in providing a universal ignition model for miniaturized ignition devices.
文摘全球气候变化导致极端降雨发生频率显著增加,暴雨中心演变更加多样化,迫切需要揭示暴雨中心演变对延河流域洪水过程的影响。通过显卡加速的地表水及其伴随输移过程模型(GPU accelerated surface water flow and associated transport model,GAST)和暴雨管理模型(storm water management model,SWMM)产流模块,模拟不同暴雨中心条件下的延河流域(河庄坪镇−姚店镇)洪水过程,分析延河流域洪水过程的变化。结果表明:当遭遇百年一遇洪水时,相对于均匀降雨,暴雨中心在水库上游时,水库可以充分发挥其调蓄功能,受灾区位数量削减率达到78%,最大水深削减率为56%;暴雨中心在水库下游时,水库的调节能力受限,受灾区位数量削减率仅为22%,最大水深削减17%;洪水淹没风险从大到小依次为现状条件下的均匀降雨、“上拦”方案实施后的均匀降雨、实施“上拦”方案下的暴雨中心在水库下游、实施“上拦”方案下的暴雨中心在水库上游。研究结果有助于量化暴雨中心演变对延河流域洪水过程的影响,指导延河流域防洪工程体系建设,从而提升延安中心城区的防灾韧性。
