The effect of roll angle on the flow over a slender body of revolution at high angles of attack

Abstract

The paper reports an experimental investigation of the effect of roll angle on the pressures and forces produced on a rigidly mounted ogivecylinder at incidences from 35O to 65O in a very low turbulence level (0.01%) wind tunnel. The primary Reynolds number of lo5 ensured laminar separation without re-attachment. The results consist Of detailed pressure measurements on the constant diameter part different noses Of Similar profile. grid was used as a simple but effective means OF flow visualisation. The results confirm that the side force is strongly dependent on roll angle and evidence i s presented of a 'regular' state for the flow. mis State is maintained over significant roll angle ranges and gives the maximum local side forces. Results from both noses it may be Of universal significance in the sense of being reproducible between corresponding tests on similar models in different facilities. Roll angle is also shown to affect the nmmal force, but less dramatically. Tests with an independently rollable nose show that the effect of roll angle is dominated by the orientation of the nose. A test technique is recommended. of the model using two A wool tuft -4 produce the same regular State Which suggests that