Numerical Investigation of Flow Structures and Interactions due to a Pitched Synthetic Jet in a Laminar Boundary Layer

A numerical investigation is conducted to study flow structures and interactions that are caused by a pitched synthetic jet placed in a laminar (Blasius) boundary layer with zero pressure gradient. Simulations are performed for various permutations of jet parameters including pitch angle (i.e., θ=60, 75, and 90), blowing ratio (i.e., Cb = 0.5, 1.0, 1.5, and 2.0), and non-dimensional actuation frequency (i.e., f̂jet=0.05, 0.1, 0.2, and 0.4). Cases corresponding to the full set of jet parameters are studied based on 2D simulations while, for selected cases, 3D simulations are also considered. In these cases, we focus on five flow structures and behaviors: a discrete train of vortex pairs, subharmonics, vortex pair switching, vortex splitting, and complex vortex interactions.