Shock wave induced separation control by streamwise vortices

Abstract

Engineering, Division of Power Engineering.Control of shock wave and boundary layer interaction finds still a lot of attention. Methods of this interaction control have been especially investigated in recent decade. This research was mostly concerned with flows without separation. However, in many applications shock waves induce separation often leads to strong unsteady effects. In this context it is proposed to use streamwise vortices for the interaction control. The results of experimental investigations are presented here. The very promising results were obtained, meaning that the incipient separation was postponed and the separation size was reduced for the higher Mach numbers. The decrease of the RMS of average shock wave oscillation was also achieved.

Control of shock unsteadiness in shock boundary-layer interaction on a compression corner using mechanical vortex generators

“…Recently, studies have been carried out to diminish the detrimental effects of SWBLI using flow control [11][12][13][14][15][16][17][18][19][20]. These techniques primarily rely on altering the characteristics of the incoming boundary-layer by adding momentum to the velocity profile close to the wall.…”

“…These techniques primarily rely on altering the characteristics of the incoming boundary-layer by adding momentum to the velocity profile close to the wall. The most popular method to accomplish this relies on the generation of vortices near the wall by the use of vortex generating (VG) devices such as micro-ramps, vane-type VG fixed at an angle to the main flow or the use of micro air-jets at an appropriate distance upstream of the region of interaction [12][13][14][15][16]. These devices generate either co-rotating or counter-rotating vortices depending upon their design and angular positions with respect to the main flow direction.…”

Supersonic flow control

“…The research status in this field also indicates that the vane-type VG shapes are superior in performance when compared to the ramp/wedge-type VGs and, therefore, more innovative designs need to be looked into to match the effectiveness of the former. Although nothing concrete could be ascertained about control location, a rough estimate indicates that this distance is to be somewhere between (15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30) x/ h (where x is the distance of the control location from the interaction).…”

“…6). Although micro-VGs have the added advantage of being mechanically rugged, simple and fail-safe, the micro-jet (MJ) control technique, which also provides similar flow control effectiveness, not only has the flexibility of switching off and on [28] or "activating on demand" but can also have the added advantage of being integrated with transpiration systems as well [29]. The former characteristic helps to eliminate the parasitic drag associated with micro-vortex generators (MVG) [25].…”

“…However, active flow control devices, as already mentioned before, can be complex, expensive and also difficult to implement and maintain [25]. Various groups in USA [29][30][31][32][33], Europe [10,28,34,35], UK [26,27], India [36,37] and China [38] are looking at different methods of shock-induced control in various areas of research applications.…”