The effect of flow curvature on the aerodynamic characteristics of an ogive-cylinder body

Abstract

SummaryThe pressure distributions over a 6:1 fineness ratio ogive cylinder model have been obtained over a wide pitch range in the rectilinear flow provided by the CoA 8 ft x 6 ft low speed wind tunnel and the curvilinear motion provided by the CoA Whirling Arm facility. The pressure distributions were integrated first to obtain the local normal-force loading distribution along the body and then the overall normal-force and pitching moment and hence the centre of normal-force.A comparison of the results showed that the main difference between the aerodynamic characteristics was a considerable positive increase in normal-force loading over the whole of the afterbody in curvilinear motion which varied little with the magnitude or sign of the pitch angle. Some smaller changes were also apparent in the forebody loading characteristics. These changes resulted in the body developing considerably more normal-force and nose-down pitching moment in curvilinear motion than in rectilinear flow with the resultant large rearward movement of the centre of normalforce.It was found possible to estimate the main features of the loadings, but the theoretical methods available did not predict very well the variations in loading obtained experimentally at the extreme beginning and end of the parallel afterbody.