Control of asymmetric flow over a blunt-nosed slender body

An innovative control device for the asymmetric flows over a blunt-nosed slender body is studied at a high angle of attack (alpha = 50 degrees). The control device is composed of a micro-particle and a blowing device. Experimental tests are conducted to study the control of asymmetric flow. Particle-image velocimetry, surface oil-flow visualizations, and pressure scanning are used to present the vortical structures, flow separations, and pressure distributions. A blow hole with a diameter of d(b) = 0.005D and a particle with a diameter of d(p) = 0.006D are placed on both sides of the nose as the micro-blowing perturbation and micro-particle perturbation (MPP), respectively, to control the behavior of the asymmetric vortices. The blowing coefficient (C-mu) through the blow hole is 0-9.42 x 10(-5). Results show that a certain and predictable pattern of asymmetric flow is first presented at C-mu = 0, owing to the certain location of MPP on the nose. Subsequently, as C-mu increases, the asymmetric flow is changed into symmetrical first and then into the opposite asymmetric flow pattern. As a result, the corresponding side-force is changed into zero and then the opposite direction. These results indicate that the pattern of asymmetric vortices and their corresponding side-forces are easily managed by changing the blowing coefficient. The evolutions of associated pressure distributions, flow separations, and vortical structures with the increase in blowing coefficient are presented in detail. Published under license by AIP Publishing.