Experimental analysis of aerodynamic characteristics in the Hyperloop system

Hyperloop aerodynamic characteristics (e.g., the pressure wave in front of the pod) are analyzed experimentally and theoretically in this study. A scaled Hyperloop aerodynamic experimental equipment that has a scale of dpod = 8.75 cm, BR = 0.34 and lt = 16 m is developed; it can be used to run experiments in the range from 160-320 m/s of vpod at approximately 1/1,000 atm (pref = 150 Pa). Further, this experiment has an observed va, which is not revealed in the analysis of the ideal case. The va is generated during the pod acceleration process and has a significant effect on vLSW. Three pressure waves (LSW1, FEW, and LSW2) are measured in front of the pod. vLSW1, vFEW, and vLSW2 are similar at vpod<250 m/s, and LSW1, FEW, and LSW2 are located in this order. However, at vpod>250 m/s, the positions of LSW1, FEW, and LSW2 become increasingly close, and LSW2 eventually catches up to LSW1 and FEW as vLSW2>vLSW1>vFEW. vLSW2 and ILSW2 are predicted theoretically assuming va = vpod. The maximum differences in the vLSW2 and ILSW2 between the experimental result and theoretical prediction are 5.66% and 7.31%, respectively. ILSW1 generated by entering the test section decreases because it moves away from the entrance; it decreases more rapidly for a high vpod. ILSW2 generated by driving the pod in the tube shows a larger value than the theoretically predicted value in the entrance region (x/lt<0.4). At x/lt>0.4, ILSW2 is close to the theoretically predicted value with a maximum difference of 10.5%. The suggested theoretical model with assumption va = vpod is in good agreement with the experiment result.(c) 2023 The Author(s). Published by Elsevier Masson SAS. This is an open access article under the CC BY-NC-ND license (http://creativecommons .org /licenses /by-nc -nd /4 .0/).