Role of flow kinematic and energetic effects in hypersonic flow control

Abstract

Different methods have been proposed by researchers for reducing the high wave drag associated with blunt bodies that are usually used in most hypersonic missions. This paper discusses some of the popular methods like increasing the blunt shock wave stand-off distance ahead of the body which can be achieved by using either a retractable aero-spike or a forward facing jet so that the hypersonic flow control is dominated by flow kinematics. Also, techniques such as concentrated energy deposition ahead of the body, heat releasing smart coating, forward facing plasma jet emanating from the stagnation zone of the blunt body have been discussed where flow energetic effects are dominant. Substantial aerodynamic drag reductions (25% to 54%) around blunt bodies have been measured in the experiments. We also review some important factors affecting the flow pathology of hypersonic flow fields when we employ different hypersonic flow control strategies.