• Numerical Simulation
• Flow control strategies
• OpenFoam
• Matlab

Impinging gas jets in the low Mach number regime assume an important role in both the academic and the industrial environment. This thesis is conducted within the von Karman Institute (VKI) research framework on the flow control for gas jets impinging on the curved walls, a configuration which is capable of promoting self-sustained oscillation of the flow. The aim was to drive the pre-design stage of a new control method via Computational Fluid Dynamics (CFD), investigating several designs and operating conditions. The simulations were carried out in OpenFoam 2.3.1 with a k-omega SST URANS approach. Starting from an uncontrolled configuration, the influence of the velocity inlet, the shape of impinging wall and the height of the curved wall has been studied.
Once identified the flow mechanism responsible for the jet oscillation, two control strategies were defined: the first aiming at hindering its occurrence; the second aiming at compensating its effects. The first approach was implemented by introducing a buffer plate in strategic locations of the flow configuration; the second was implemented via a thrust vectoring technique using a secondary injection and a Coanda surface. The numerical investigation of these configurations was conducted in parallel with high speed flow visualization from other members of the VKI team and has finally lead to the mechanical design and construction of a new nozzle, currently under investigation in the VKI laboratories.