Quiet Flow Characteristics of the NASA-Ames Laminar Flow Supersonic Wind Tunnel for Mach 1.6 Transition Studies

Low-disturbance or 'quiet' wind tunnels are an essential part of any meaningful boundary layer transition research. In particular, the receptivity of supersonic boundary layers to wind tunnel disturbances can significantly alter the transition phenomena under investigation on a test model. Consequently, considerable study has gone into the design of a new wind tunnel to provide quiet (low-disturbance) flow, encompassing both theoretical and experimental efforts. Our pilot (eighth-scale) supersonic wind tunnel was reported in 1992. NASA-Ames Fluid Mechanics Laboratory (FML) commissioned a quiet wind tunnel in 1994 to support Supersonic Laminar Flow Control (SLFC) research. Known as the Laminar Flow Supersonic Wind Tunnel (LFSWT), this tunnel is designed to operate at potential cruise Mach numbers and unit Reynolds numbers (Re) of the High Speed Civil Transport (HSCT). The need to better understand the transition phenomena on the leading edge region of swept (HSCT) wings provided the impetus for building the LFSWT. Additional information is contained in the original extended abstract.