EXPERIMENTAL INVESTIGATION OF DRAG REDUCTION ON AHMED MODEL USING A COMBINATION OF ACTIVE FLOW CONTROL METHODS

Aerodynamic drag is an important factor in vehicles fuel consumption. Pressure drag which is the main component of total drag is a result of boundary layer separation from vehicle surface. Flow control methods are applied to avoid or at least delay separation. Depending upon whether these methods consume energy to control the flow or not, they are called active or passive control methods. In this paper, we investigate experimentally, the effect of suction and base bleeding as two active flow control methods on aerodynamic drag reduction of Ahmed body with 35 degree rear slant angle. Suction in boundary layer is applied in order to delay flow separation by extracting flow particles with low kinetic energy near the model surface and the sucked air is blown into the wake of the model to increase the static pressure of the wake region. The location of suction is at the beginning of rear slant surface and the location of blowing is at the middle part of rear vertical part of the model. Moreover, the effect of change in control flow rate and suction and base bleeding area is investigated.