Note on the use of the three-dimensional shockwave recorder for studying interference in a supersonic wind tunnel

Abstract

A description is given of the three-dimensional shock-wave recorder which has been used to investigate wind-tunnel interference on a sting-mounted wing having 50 deg of sweepback. Diagrams of the shock-wave patterns round the wing are given for the following conditions of Mach number and incidence:- M = 1.4 Incidence = 4 deg, M = 1.6 Incidence = 4 deg, M = 1.8 Incidence = 0 deg. From these diagrams it can he inferred that the outboard portion of the particular wing tested suffers interference from the tunnel Walls at M = 1.4. At the higher Math numbers the model behaves effectively as if it were in free air. In order to use the three-dimensional shock-wave recorder, the wind-tunnel working-section requires a window whose length is at least three times the tunnel width and which extends equal distances ahead of and behind the model. This is a very serious drawback to the general use of the method. The analysis of the photographic records is straightforward, though rather tedious.