Experimental Study of Boundary Layer Flow Control Using an Array of Ramp-shaped Vortex Generators

Abstract The objective of this study was to obtain a database on the flowfield past an array of vortex generators (VGs) in a turbulent boundary layer. All testing was carried out in a low speed wind tunnel with a flow velocity of 29 ft/sec, giving a Reynolds number of 17,500 based on the width of the VG. The flowfield generated by an array of five ramp-shaped vortex generators was examined with hot wire anemometry and smoke flow visualization. The magnitude and extent of the velocity increase near the wall, the penetration of the velocity deficit into the core flow, and the peak streamwise vorticity are examined. Influence of various parameters on the effectiveness of the array is considered on the basis of the ability to pull high momentum fluid into the near wall region. Nomenclature c Ramp chord length h Ramp height s Ramp spacing u’ Turbulence intensity in streamwise direction U Local streamwise mean velocity U ∞ Freestream velocity w Ramp width x Cartesian coordinate in streamwise direction (Fig. 1)