Periodic Behavior of Longitudinal Vortex Pair by Active Vortex Generator

Abstract

The present paper describes dynamic interaction based on the phase averaged characteristics of the longitudinal vortices downstream of several pairs of active vortex generators with controlled the angle of attack in the turbulent boundary layer. The objective is to clarify experimentally how the vortex configurations have an effect on circulation and Reynolds stress. This study focuses on circulation to examine strength of vortex pairs and development of the vortex core region. Attention is also paid on Reynolds shear stress ( , ) to understand the structures imposed by vortex interaction such as convection. uv − uw − Nomenclature H = height of vortex generator (= 20 mm) L = base width of vortex generator ReΘ = Reynolds number based on momentum thickness S = spacing between the vortex generators U = mean velocity in the X direction Uref = reference velocity (= 16.0 m/s) X = streamwise coordinate Y = transverse coordinate Z = spanwise coordinate δ = boundary layer thickness θ = momentum thickness ΩX = stremwise vorticity