Active control for airfoil with smart slat / Amr Mohamed Abdelhamid Mohamed Halawa ; Supervised Basman Mohamed Nabil Elhadidi

Thesis (M.Sc.) - Cairo University - Faculty of Engineering - Department of Aerospace Engineering

In this thesis, active flow control was applied on a DU-96-W-180 airfoil to improve its aerodynamic properties. A flow simulation was done around this airfoil for incompressible unsteady low Reynolds Number flow using OpenFOAM® at high angle of attack. An active slat was used to allow for periodic excitation of the flow at its domain dominant frequencies. In order to obtain these frequencies, a frequency analysis was performed using Fast Fourier Transform (FFT). These frequencies will help in controlling the inherent instabilities in the boundary layer. The most dominant frequency was found to be f {u0305}=0.68 in the wake region. Due to complexity of nonlinear unsteady flows, modal decomposition method; namely proper orthogonal decomposition (POD) was applied in conjunction with the Modified Linear Stochastic Measurement (MLSM) to achieve a reduced order model with high accuracy and low computational cost. It was found that using only 3 POD modes, most of the system energy (up to 99%) was captured. Besides, using only two pressure sensors, one upstream and the other downstream, the surface pressure field was reconstructed with high accuracy. Finally, active flow control simulations was applied using different excitation frequencies where improved performance was achieved in the lift coefficient by 8% and overall aerodynamic efficiency by 3%.

Issued also as CD