Book Description

An experimental study is conducted to determine the dependence of vortex generator geometry and impinging flow conditions on shed vortex circulation and crossplane peak vorticity for one type of vortex generator. The vortex generator is a symmetric airfoil having a NACA 0012 cross-sectional profile. The vortex generators are mounted either in isolation or in a symmetric counter-rotating array configuation on the inside surface of a straight pipe. The turbulent boundary layer thickness-to-pipe radius ratio is 0.17. Circulation and peak vorticity data are derived from crossplane velocity measurements conducted at or about 1 chord downstream of the vortex generator trailing edge. Shed vortex circulation is observed to be proportional to Mach number, angle of attack and space to boundary-layer thickness. With these parameters held constant, circulation is observed to fall off in monotonic fashion with increasing airfoil aspect ratio. Shed vortex peak vorticity is also observed to be proportional to the aforementioned parameters. Unlike circulation, however, peak vorticity is observed to increase with increasing aspect ratio.