Controlling The Base Pressure Of A Supersonic Body Subjected To Sudden Expansion Flow Using Micro Jet

Abstract

Researchers involved in the area of external aerodynamics have been particularly bothered with the issue of the sudden expansion of the flow at the rear end of the projectile and its relationship to the base pressure. One specific issue particularly of concern is that the pressure at the base of the projectile is less than the ambient pressure. The base pressure control method mentioned in most of the earlier studies is passive control methods, providing sufficient scope to research the impact of active control methods. The present study is experimental research, conducted on the sudden expansion of the flow in a supersonic nozzle. The study focuses on the effectiveness of controlling base pressure using micro-jets (active control method). It aims to highlight the variation in base pressure, with the control method and without it. The parameters considered are area ratio, length-to-diameter (L/D) ratio, and nozzle pressure ratio (NPR). We used area ratios that were not used earlier for Ma = 2.58. The effect of the above parameters on the base pressure is presented. The result suggests that at a higher NPR and higher L/D ratio, the reattachment of the flow occurs with the use of micro-jets. Also, for a constant area ratio with variation in L/D ratio and NPR, it is found that the base pressure considerably decreases.