Jiang ZHANG , Xiaoyan HE , Handong MA ,Yongming QIN
DOI Number XXX-YYY-ZZZ
Conference Number HiSST 2018_36201052
The flow characteristics around the blunt body with forward-facing jet and spike are investigated through wind tunnel experiments, which include the mechanism of steady mode and unsteady mode. The dynamic-force measurement, dynamic-pressure measurement and schlieren are involved. The results indicate that there are the steady mode and the unsteady mode for the flow field around the blunt body with the combination of forward-facing jet and spike. The flow is steady as the pressure ratio of the supersonic jet is higher than the critical pressure ratio, while it is under unsteady mode as the pressure ratio of the supersonic jet lower than the critical pressure ratio. The drag of the blunt body decreases with the increasing of the length of spike until the length of the spike reaches a certain value. With the enhancement of jet pressure ratio the strength of the reattached shock waves is weakened significantly, which is beneficial to eliminate the hot spot on the shoulder of blunt body. The pressure on the suface surrounded by the reattach shock waves is fluctuant intensively under the unsteady mode, which is induced by the self-excited oscillations of shock waves around the blunt body. The dominant frequency of the self-excited oscillation decreases with the increasing of jet pressure ratio. The mechanism of self-excited oscillation is that the ambient pressure around the jet exit cannot be persistently balanced when jet pressure ratio is lower than the critical pressure ratio.