2341 2つの不足膨張衝突噴流に関する研究(S46-2 圧縮性流れの基礎と応用(超音速流2),S46 圧縮性流れの基礎と応用)  [in Japanese] 2341 Research relevant to underexpanded impinging jet of Dual nozzle  [in Japanese]

In this paper, twin underexpanded impinging jets are experimentally studied. The experiments were performed by static pressure fluctuation measurements on the wall and by schlieren method. The main parameters for the twin jets are the nondimensional distance between the two nozzle centers H/D 2.0, the nozzle to plate separation L/D 2.0 and 3.0 and the pressure ratio defined by P_0/P_b 3.0〜4.0, where D is the diameter of each nozzle exit, P_0 the stagnation pressure and P_b the back pressure. In case of L/D 2.0 and P_0/P_b 3.75, a Mach disk repeats the formation and disappearance due to the unsteadiness of the so called Fountain flow affecting the both main jet boundaries. It is found that severe pressure fluctuations were observed under the above condition.