TECHNICAL NOTE D- 1626 EXPERIMENTAL PRESSURES AND TURBULENT HEAT-TRANSFER COEFFICIENTS ASSOCIATED WITH SINUSOIDAL PROTUBERANCES ON A FLAT PLATE AT A MACH NUMBER OF 3

SUMMARY An exploratory investigation was made to determine the local effects on aero- dynamic heating produced by three-dimensional sinusoidal-type skin buckles of var- ious depths. Tests were made at a Mach number of 3.0, a stagnation pressure of 200 pounds per square inch absolute, a stagnation temperature of 300' F, and a free-stream Reynolds number per foot of approximately 14 X 10 6 . obtained from one set of test specimens and pressures from another. The test results, presented in terms of Stanton numbers and pressure coefficients, show that marked increases or decreases in aerodynamic heating and pressure can result from changes in contour produced by skin buckles. ' Temperatures were INTRODUCTION Analytical calculation of the heat transfer to the external skin of super- sonic vehicles generally assumes that the surface is smooth and aerodynamically clean with the local flow conditions known. Such predictions may be invalidated by changes in the local flow characteristics resulting from surface protuberances or thermally induced buckles and distortions in the outer skin surface. example, refs. 1,