Computational Investigation on Aero-optic Aberrations of a Supersonic Interceptor with Multiple Lateral Jets

This paper presents a computational investigation of aero-optic aberrations that arise when multiple lateral jets are used to control a supersonic interceptor. Reynolds-averaged Navier-Stokes simulations are employed to analyze the flow field under various conditions, including altitudes ranging from 30 to 50km, angles of attack from -15° to 25°, with four distinct jet configurations. Aero-optic effects of flow structure are analyzed by calculating the optical path difference (OPD) as a function of beam arclength parameter and normalizing it through scale analysis. When the jet flow does not interfere with the seeker's field of view (FOV), normalized OPD is predominantly governed by the bow shock and conical expansion region generated in front of the vehicle head and exhibits similar profiles along the beam path for all altitudes. When the jet flow is introduced, separation shock and bubble induced by jet interaction can obscure the seeker's FOV under altitudes over 35km and AOA over 15°. Multi-jet cases at 35km show that the separation bubble blocks a larger portion of the seeker's FOV and increases normalized OPD at higher AOA as per-jet strength increases. Overall, the difference in Strehl ratio between the jet on/off cases is about 1% at 35km.