The interaction between the car-body vibration and aerodynamic performance of the train becomes more prominent motivated by the vehicle’s light-weighting design.To address this topic,this study firstly analyzes the p...The interaction between the car-body vibration and aerodynamic performance of the train becomes more prominent motivated by the vehicle’s light-weighting design.To address this topic,this study firstly analyzes the posture characteristics of the car-body based on the previous full-scale test results.And then the aerodynamic performance under different vibration cases(different car-body roll angles)is studied with an improved delayed detached eddy simulation(IDDES).The results revealed that car-body rolling had a significant impact on the aerodynamic behavior of bogies,which significantly increased the lateral force and yaw moment of a bogie and further may have aggravated the operational instability of the train.The unbalanced distribution of the longitudinal pressure on both sides of the bogie caused by the car-body rolling motion was the primary cause for the bogie yaw moment increase.The tail vortex of the train was also affected by the car-body rolling,resulting in vertical jitter.展开更多
A principle of generating the nonlinear large-amplitude internal wave in a stratified fluid tank with large cross-section is pro- posed according to the ＇jalousie＇ control mode. A new wave-maker based on the princip...A principle of generating the nonlinear large-amplitude internal wave in a stratified fluid tank with large cross-section is pro- posed according to the ＇jalousie＇ control mode. A new wave-maker based on the principle was manufactured and the experi- ments on the generation and evolution of internal solitary wave were conducted. Both the validity of the new device and ap- plicability range of the KdV-type internal soliton theory were tested. Furthermore, a measurement technique of hydrodynamic load of internal waves was developed. By means of accurately measuring slight variations of internal wave forces exerted on a slender body in the tank, their interaction characteristics were determined. It is shown that through establishing the similarity between the model scale in the stratified fluid tank and the full scale in the numerical simulation the obtained measurement re- suits of internal wave forces are confirmed to be correct.展开更多
基金Project(BX2021379)supported by the China National Postdoctoral Program for Innovative Talents。
文摘The interaction between the car-body vibration and aerodynamic performance of the train becomes more prominent motivated by the vehicle’s light-weighting design.To address this topic,this study firstly analyzes the posture characteristics of the car-body based on the previous full-scale test results.And then the aerodynamic performance under different vibration cases(different car-body roll angles)is studied with an improved delayed detached eddy simulation(IDDES).The results revealed that car-body rolling had a significant impact on the aerodynamic behavior of bogies,which significantly increased the lateral force and yaw moment of a bogie and further may have aggravated the operational instability of the train.The unbalanced distribution of the longitudinal pressure on both sides of the bogie caused by the car-body rolling motion was the primary cause for the bogie yaw moment increase.The tail vortex of the train was also affected by the car-body rolling,resulting in vertical jitter.
基金supported by the National Natural Science Foundation of China(Grant No.11072267)the National High Technology Research and Development Program of China(Grant No.2008AA09Z316)the Pre-Research Foundation of PLA University of Science&Technology(Grant No.KYLYZLXY1202)
文摘A principle of generating the nonlinear large-amplitude internal wave in a stratified fluid tank with large cross-section is pro- posed according to the ＇jalousie＇ control mode. A new wave-maker based on the principle was manufactured and the experi- ments on the generation and evolution of internal solitary wave were conducted. Both the validity of the new device and ap- plicability range of the KdV-type internal soliton theory were tested. Furthermore, a measurement technique of hydrodynamic load of internal waves was developed. By means of accurately measuring slight variations of internal wave forces exerted on a slender body in the tank, their interaction characteristics were determined. It is shown that through establishing the similarity between the model scale in the stratified fluid tank and the full scale in the numerical simulation the obtained measurement re- suits of internal wave forces are confirmed to be correct.
