Energy-Deposition to Reduce Skin Friction in Supersonic Applications

NASA has drawn attention to an impending need to improve energy-efficiency in low supersonic (M<~3) platforms. Aerodynamic efficiency is the foundation of energy-efficient flight in any regime, and low drag is one of the fundamental characteristics of aerodynamic efficiency. For supersonic aircraft, drag can be broadly decomposed into four components: viscous or skin friction drag, lift-induced drag, wave or compressibility drag, and excrescence drag. The relative impact of these four drag forces depends upon vehicle-specific characteristics and design. However, viscous skin friction drag stands out as particularly significant across most classes of flight vehicles. Therefore, effective techniques to reduce skin friction drag on a vehicle will have a major and far-reaching impact on flight efficiency for low supersonic aircraft. In an effort to address the need for increased aerodynamic efficiency of low supersonic vehicles, PM & AM Research, in collaboration with Texas A & M University, propose to demonstrate the feasibility of depositing energy using basic, well-demonstrated techniques along the surface in supersonic flow to control/compress/forcibly-move the boundary layer fluid by creating a low-density "bubble-like" region, thereby reducing the viscous skin friction. If successful, this solution will reduce the drag experienced by a low supersonic platform, allowing vehicles to exhibit increased aerodynamic efficiency.