Thesis (Ph.D.) - Cairo University - Faculty of Engineering - Department of Aerospace Engineering

The study is began with a wide numerical investigation on the deep dynamic stall phenomenon of unsteady flow around oscillating NACA 0012 airfoil at low Reynolds number. The numerical work uses two experimental cases for validating the predicted hysteresis loops and flow structure. The investigation is performed by solving the Navier-Stokes equations with three turbulence models Spalart-Allmaras, k{u025B}-Realizable and k{u0277}-SST. The results show that the k{u0277}-SST is a good model for predicting the dynamic stall stages especially the detecting of leading edge vortex (LEV) and post stall shedding comparing to the experimental data. Comparison between static and dynamic situation is performed. Effects of reduced frequency and oscillation amplitude, effects of airfoil thickness and effects of wing end plates on the dynamic stall phenomenon are studied. Fifteen cascading configuration are studied under the same operating conditions including upper cascading, upper forward cascading, and lower forward cascading during oscillation motion. Comparison between the overall generated torque with azimuthal angle resulting from the CFD and DMST of VAWT models in Darrieus motion is performed including forward and backward auxiliary airfoils with specific offset distances effects. Three cases of vertical axis wind turbine are tested experimentally in static situation

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