Base Pressure Control using Micro-jets in Supersonic Flow Regimes

<p>Base pressure plays a vital role in aerospace-related applications and its control is essential in reduction of drag and improving fuel consumption. Low pressure at the base of Rockets, Missiles, bombs and shells are a very common problem happening at transonic and supersonic speeds. In most of the cases there is a significant dip in pressure at the base region which will have implications on the design of aerospace vehicles. This paper presents an experimental investigation carried out for flow control at supersonic regimes. Experiments were conducted to measure the base pressure in the base region and wall pressure distribution in the enlarged duct at Mach 1.25 and 2.0, for L/D = 10, for four area ratios namely, 2.56, 3.24, 4.84, and 6.25. From the results it is found that active control in form of micro-jets is effective in boosting base pressure only at higher Mach numbers with larger area ratios at under-expanded conditions. Wall pressure flow field reveals that the quality of the flow with and without control is almost identical and there is no adverse effect of the control mechanism on the flow field of the duct. The variation in reattachment point along the downstream of the duct has very minimal effect with micro-jets as control.</p>