Research at DLR Gِttingen on bluff body aerodynamics, drag reduction by wake ventilation and active flow control

This paper outlines some experimental investigations on aerodynamics of bluff bodies which have been carried out at the former DLR Institute of Fluid Mechanics, now Institute of Aerodynamics and Flow Technology. Examples given here include (a) drag reduction by passive ventilation of the wake of the body, (b) reduction of the drag of automobiles by shape optimisation to eliminate or at least decrease trailing vortices, (c) optimisation of front and rear ends of high speed trains, (d) determination of the main sources of aerodynamic noise of high velocity trains which result from unsteady flow separations, (e) experiments on active flow control to delay flow separation.