Reasonable pressure tap layout to measure the aerodynamic forces of a train at different yaw angles

Abstract

The present work studies the aerodynamic loads of a train for different yaw angles from 5.87° to 30° by using the detached-eddy simulation (DES) method. Furthermore, based on the pressure integral method, a reasonable layout of the pressure taps on the train under a crosswind is studied to obtain the aerodynamic forces and moments that are used for a comparison with the results of the wind tunnel test. Considering the lower errors of the pressure integral results and fewer number of pressure taps comprehensively, the pressure integral method in the case of 15–4 (15 represents the tap quantity along the length direction, 4 represents the tap quantity along the height/width direction) on the head car and tail car, the case of 14–4 on the middle car are relatively good among the nine cases discussed in this paper. Compared to the results of the wind tunnel test, for the head car, the maximum error of the side force coefficient (Cy), rolling moment coefficient (Mx), and yawing moment coefficient (Mz) is all less than 10% for yaw angles from 5.87° to 90°, and the maximum errors of lift force coefficient (Cz) is less than 20% for yaw angles from 10.2° to 90°; for the middle car, the maximum error of Cy is less than 20% for yaw angles from 5.87° to 90°, and the maximum error ofCz,Mx and Mz is all less than 15% for yaw angles from 5.87° to 90°; for the tail car, the maximum error of Cy,Cz,Mx and Mz is all less than 15% for yaw angles from 10.2° to 90°.