Transient computational investigation on the ejection seat’s aerodynamic coefficients at subsonic Mach number

Abstract

In this study, the commercially available CFD software ANSYS-Fluent is used to conduct a three-dimensional unsteady-state analysis of the aerodynamic coefficients of an ejection seat system. The aerodynamic coefficients are calculated by solving Reynolds-averaged Navier–Stokes equations. ANSYS meshing software is utilized to create an unstructured grid of tetrahedral cells for this analysis. The validation of the numerical methodology is performed initially on a sphere at subsonic Mach number (Ma) for different Reynolds numbers (Re) before the validation of the ejection seat system. The computed unsteady-state results are compared with the experimental and available numerical results for both the sphere and the ejection seat. Later the aerodynamic coefficients of the ejection seat are further investigated at Ma = 0.7 by changing the angle of attack (α) and yaw angle (β). The findings of this study show that the magnitude of the axial force coefficient (C_X) and values of the side force coefficient (C_Y), normal force coefficient (C_Z), pitching moment coefficient (C_m), yawing moment coefficient (C_n), and rolling moment coefficient (C_l) changes with the variation of the α and β.