Unsteady Jets in Crossflow Available to Purchase

The effect of periodic perturbation on a jet in a cross-flow (JICF) is reviewed. In the first part of the paper, flow visualization results from several past works are discussed. Beginning with a description of the characteristic vortex systems of a JICF it is shown that specific perturbation techniques work by organizing and intensifying specific vortex systems. Oscillatory blowing works primarily through an organization of the shear layer vortices. A mechanical perturbation technique is found to organize the wake vortices. In the second part of the paper, results of an ongoing experiment involving another mechanical perturbation technique are discussed. It involves two tabs at the orifice exit whose asymmetry in placement is reversed periodically. It directly modulates the counter-rotating vortex pair (CVP). Effects of the perturbation for an array of three adjacent orifices are explored. The flowfield data show an improvement in mixing compared to the unperturbed case.