Aero-optical and aero-heating effects of supersonic turbulent boundary layer with a tangential wall-injection film

Abstract

Film cooling via tangential wall injection is universally employed to alleviate serious aerodynamic heating of the optical window in high-speed target-seeking vehicles; nevertheless the imaging quality should be concomitantly concerned due to the turbulence-aberrated aero-optical phenomenon. This flow phenomenon can be essentially abstracted into the combinational mixing layer and turbulent boundary flow configuration, enabling numerical investigation using an explicit fifth-order weighted compact nonlinear scheme (WCNS-E-5) and a ray-tracing method. The current study considers both the aero-optical effect in a prescribed light pupil and the wall temperature under adiabatic conditions, with snapshots of vorticity contours in the symmetric plane and the wall normal density fluctuation introduced as auxiliary variables for analyzing the flowfield behavior. A parametric investigation on tangential wall injection is conducted by altering the Mach number, total temperature, and total pressure consequently via a variable-controlling procedure. The results reveal that the mutual realization of aero-optical and aero-heating reduction presents considerable difficulty, so that the future optimization of the operating conditions is suggested for engineering applications.