Simulation and modeling of synthetic jets

This chapter gives a comprehensive review on the state-of-the-art numerical simulation and modeling of synthetic jet (SJ), an oscillatory, zero-netmass-flux jet that has great potential in flow control. The numerical techniques dealing with the SJ oscillation, laminar-turbulent transition, and turbulence in quiescent conditions are introduced first. From the CFD simulations, the flow physics associated with SJs issuing from offices of different shapes, mainly highaspect-ratio rectangular slots and low-aspect-ratio rectangular or circular orifices, are then summarized and discussed. Low-dimensional models that are used for fast prediction of the performance of SJ actuators in quiescent conditions are also introduced. The review then focuses on the CFD simulations of SJ interaction with cross flows, including both attached and separated flows. Different numerical methods are introduced and compared. The flow physics associated with SJs interacting with laminar boundary layers, turbulent boundary layers, different types of separated flows, as well as flows around an airfoil are also summarized and discussed. In the end, research about the coupling of CFD simulation or lowdimensional modeling with optimization and control algorithms for SJ-based flow control is briefly reviewed. We hope this chapter provides a better picture of the state-of-the-art numerical simulation and modeling of SJs for the flow separation control applications and future researchers in this field can benefit from reading it.