Enhancing Pressure Recovery in a Serpentine Duct using Active Flow Control

The turbulent flow fields in a three-dimensional (3D) diffuser with massive flow separation are being computationally investigated using high-fidelity Large Eddy Simulations across a spectrum of Mach numbers from Ma = 0.4 to 0.8. For verification and validation, the unsteady characteristics and 3D flow structures are compared against temporally- and spatially-resolved stereoscopic PIV experiments conducted at the Center for Flow Physics and Control at Rensselaer Polytechnic Institute. This study examines the growth and dynamics of large-scale vortical structures as produced by multiscale physics. Similar to the experimental setup, the effects of pulsed jet arrays, segmented jets, and 2D steady and unsteady jets, along with side-wall suction, on the mean and turbulent properties will be meticulously investigated. Specifically, the turbulent intensities and turbulent kinetic energies are analyzed both with and without flow control, and their outcomes are benchmarked against experimental data. The primary objective of this research is to enhance pressure recovery and minimize flow distortion using active flow control techniques. This marks unique active control strategies for internal flows which is validated and verified experimentally, with additional determination of actuation amplitude and frequency in numerical simulations under various conditions. Following validation, further simulations will be conducted in higher Mach number regimes where experimental data is lacking, an approach anticipated to be highly beneficial for manipulating flows limited by design constraints.