With the expansion of tunnel construction scale,accurate modeling of 3D unsteady flow fields in ultra-long tunnels requires high computational resources.In this study,a resistance compensation method based on the St a...With the expansion of tunnel construction scale,accurate modeling of 3D unsteady flow fields in ultra-long tunnels requires high computational resources.In this study,a resistance compensation method based on the St and Eu similarity criterion is proposed to construct the simplified model to rapidly and precisely replicate the train-driven unstable airflow.A 6000 m ultra-long tunnel is utilized as a reference model and simplified models with the scale ratio varying from 80%to 10%are developed to assess the method performance.The multi-region dynamic mesh model is employed to simulate train tracking motion.After weighing the computational accuracy and efficiency,the results show that 20%is the optimal scale ratio.The unsteady wind speed of the simplified model deviates 6.96%from the reference model,while the simulation computation time is reduced by 85.01%.On this basis,the simplified model is applied to analyze the impacts of tunnel friction coefficients,blockage rates,train lengths and speeds,and departure intervals.The mean bias error(MBE)and Pearson correlation coefficient(PCC)are within 10%and over 0.8 respectively,confirming the reliability of the simplified model.The resistance compensation method is a crucial technique to improve the accuracy and efficiency of the unsteady flow field in ultra-long tunnels.展开更多
基金supported by the Laboratory Basic Research Program of China State Railway Group Co.,Ltd.(L2021G011).
文摘With the expansion of tunnel construction scale,accurate modeling of 3D unsteady flow fields in ultra-long tunnels requires high computational resources.In this study,a resistance compensation method based on the St and Eu similarity criterion is proposed to construct the simplified model to rapidly and precisely replicate the train-driven unstable airflow.A 6000 m ultra-long tunnel is utilized as a reference model and simplified models with the scale ratio varying from 80%to 10%are developed to assess the method performance.The multi-region dynamic mesh model is employed to simulate train tracking motion.After weighing the computational accuracy and efficiency,the results show that 20%is the optimal scale ratio.The unsteady wind speed of the simplified model deviates 6.96%from the reference model,while the simulation computation time is reduced by 85.01%.On this basis,the simplified model is applied to analyze the impacts of tunnel friction coefficients,blockage rates,train lengths and speeds,and departure intervals.The mean bias error(MBE)and Pearson correlation coefficient(PCC)are within 10%and over 0.8 respectively,confirming the reliability of the simplified model.The resistance compensation method is a crucial technique to improve the accuracy and efficiency of the unsteady flow field in ultra-long tunnels.
