Pdf-File.pdf

A numerical investigation of a Jet and Vortex Actuator (JaVA) for active flow control in a flat plate boundary layer flow was conducted. JaVA is an oscillatory, zero-net-mass flux actuator that can delay boundary layer transition and has been shown to induce various flow types, including angled and vertical jets, wall jets, and vortex flows. The study used a commercial unsteady, incompressible Navier-Stokes solver to simulate the flow fields generated by JaVA in a water channel, and the results were validated by visualization experiments. The numerical results showed that JaVA affects the boundary layer profile considerably, making it more resistant to flow separation, and that the characteristics of the boundary layer flow, such as the free stream velocity and boundary layer profile, are important for JaVA performance. The effects of JaVA on various boundary layer flow characteristics, including displacement thickness, momentum thickness, energy thickness, and friction coefficient, were reported, and a new dimensionless parameter, the jet-to-free stream ratio, was introduced to account for the free stream velocity. The study can be used to steer the governing parameters effectively for an improved actuator design.