Base flow investigation behind axi- and non-axisymmetric blunt bodies

Abstract

Experimental investigations of the flow field in the near-wake of blunt afterbodies are presented. All the measurements were performed either by means of a two- or a three-dimensional frequency shifted laser Doppler velocimeter. Experiments were conducted in a blow-down type annular nozzle whose Mach number variation is ranged between 0.2 and 0.9. Models consist of a cylindrical afterbody, a conical and a triangular boattail. Results include mean velocities and the corresponding mean square velocity fluctuations. They show some interesting features of the mean flow field and give accurate information about afterbody flows like local flow direction, size and shape of the recirculating regions, rear stagnation point location and the differences in flow structure. Comparison is made with known calculated and experimental results already published.Experimental investigations of the flow field in the near-wake of blunt afterbodies are presented. All the measurements were performed either by means of a two- or a three-dimensional frequency shifted laser Doppler velocimeter. Experiments were conducted in a blow-down type annular nozzle whose Mach number variation is ranged between 0.2 and 0.9. Models consist of a cylindrical afterbody, a conical and a triangular boattail. Results include mean velocities and the corresponding mean square velocity fluctuations. They show some interesting features of the mean flow field and give accurate information about afterbody flows like local flow direction, size and shape of the recirculating regions, rear stagnation point location and the differences in flow structure. Comparison is made with known calculated and experimental results already published.