Abstract: Relamination of a boundary layer formed in supersonic flow over the leading edge of a swept airfoil is accomplished using at least one band, especially a quadrangular band, and most preferably a square band. Each band conforms to the leading edge and the upper and lower surfaces of the airfoil as an integral part thereof and extends perpendicularly from the leading edge. Each band has a height of about two times the thickness of the maximum expected boundary layer.

Abstract: An improved test section 16 for a supersonic or hypersonic wind tunnel 10 is disclosed wherein the model tested is shielded from the noise normally radiated by the turbulent tunnel wall boundary layer. A vacuum plenum 23 surrounds spaced rod elements 28 making up test chamber 16 to extract some of the boundary layer as formed along the rod elements during a test to thereby delay the tendency of the rod boundary layers to become turbulent. Novel rod construction involves bending each rod slightly prior to machining the bent area to provide a flat segment 29 on each rod for connection with the flat entrance fairing 31. Rods 28 and fairing 31 are secured to provide a test chamber incline on the order of 1.degree. outward from the noise shield centerline to produce up to a 65% reduction of the root-mean-square (rms) pressure over previously employed wind tunnel test sections at equivalent Reynolds numbers.

Abstract: Apparatus for directly measuring the quantity .sqroot..rho.ck of a test specimen such as a wind tunnel model where .rho. is the density, c is the specific heat and k is the thermal conductivity of the specimen. The test specimen and a reference specimen are simultaneously subjected to the heat from a heat source. A thermocouple is attached to the reference specimen for producing a first electrical analog signal proportional to the heat rate Q that the test specimen is subjected to and an infrared radiometer that is aimed at the test specimen produces a second electrical analog signal proportional to the surface temperature T of the test specimen. An analog-to-digital converter converts the first and second electrical analog signals to digital signals. These digital signals are applied to a computer for determining the quantity .sqroot..rho.ck by computing the quantity ##EQU1## WHERE T.sub.