Numerical simulation of the interaction of a circular synthetic jet with a boundary layer

In this work, a 3D numerical simulation of circular synthetic jets issued into a laminar boundary layer developing over a flat plate was undertaken in a complementary manner alongside with an experimental study with the aim of achieving an improved understanding of the fluid mechanics underlying the interaction process between the synthetic jets and the boundary layer. The simulation was carried out in FLUENT at two diaphragm operating conditions, which produced two distinctly different vortical structures and shear stress footprints on the wall. The simulation results were validated using experimental data and a good agreement was achieved. The temporal evolution of coherent structures formed as the result of this interaction was examined using the Q-criterion. The hierarchy of the coherent structures was established which provided a credible explanation of the wall shear stress pattern observed in both the experiment and the simulation. The high spatial resolution in the near-wall region and 3D nature of the simulation results provide the information about the flow field which is not only consistent with but also additional to that from the experiment, leading to an improved understanding of the interaction process between the synthetic jets and the boundary layer and its resultant structures.