NACA-TN-3170

Abstract

Wind-tunnel tests of a body of revolution with a circular nose inlet were conducted at low speeds to ascertain some of the effects of inlet lip bluntness and profile diffuser performance and body drag. The tests were conducted at free-stream Mach numbers up to 0.330 with inlet flows from zero through choking. Both the angle of attack and the angle of yaw of the body were 00 throughout the investigation. <br>A sharp inlet lip profile was tested in addition to five circular arc and two elliptical profiles the various profiles were compared in terms of their shapes and contraction ratios, the ratio of the area circumscribed by the leading edge of the inlet lip to the minimum inlet area. As would be expected, the sharp lip provided the poorest pressure recovery for mass-flow ratios greater than 1.0 for all of the Mach numbers of the test. The improvement over the internal flow characteristics of the diffuser with the sharp lip, cause by a slight bluntness of the lip of the inlet, depended to only a small extent on the shape of the lip profile. However, for moderate bluntness the effect of the shape of the profile assumed importance, with an elliptical of the shape of the profile assumed importance, with an elliptical profile providing better pressure recovery than a circular profile.