Three-dimensional flow dynamics and control of nominally two-dimensional shedding bodies

The present doctoral research is based on an experimental investigation that provides fundamental understanding for the flow dynamics in asymmetric wake of a blunt and divergent trailing edge airfoil (DTE), at high Reynolds numbers. This fundamental insight is then exploited to develop optimized flow control strategies. Furthermore, the applicability of such efficient flow control methods to bridge deck sections exhibiting vortex induced vibration problem is investigated.; The research work sheds light on the airfoil near wake flow coherent structures and their downstream evolution. Spanwise von Karman vortices as well as streamwise vortices are identified in the near wake. Their spatial arrangement is determined throughout conducting simultaneous multi-point hot-wire measurements. The sensitivity of the airfoil wake versus different levels of free stream turbulence (FST) and angles of attack is examined. The FST affects the shapes of turbulence profiles and accelerates the wake decay rate. The results suggest that the statistical spanwise distribution of the streamwise vortices is independent of FST effects and angle of attack as long as the Strouhal number remains approximately similar.; Information related to the airfoil surface flow is quantified throughout surface pressure and skin friction measurements. Both measurement techniques led to accurate determination of the airfoil profile drag.; Controlling the wake vortex shedding and base drag throughout flow control methods developed from information related to the airfoil natural near wake topology is investigated: vortex generators (VGs) and spanwise sinusoidal perturbation method (SSP). Both flow control methods significantly suppress vortex shedding. The SSP has the advantage of reducing the base drag. Applying a round trailing edge is also examined. The round trailing edge reduces base drag: however, it enhances vortex shedding strength.; The effectiveness of SSP in controlling vortex induced vibrations (VIV) in a plate girder bridge section model is examined. The results indicated that after strategically selecting the design parameters of SSP, the VIV response is significantly suppressed. However, the SSP efficiency is found to be vibration response mode dependent.; Keywords. blunt trailing edge airfoils, vortex shedding, wake flows, coherent flow structures, free stream turbulence, self-similarity, surface flows, drag measurements, flow control, plate girder bridge sections, vortex induced vibration...