S0504-1-1 超音速矩形ジェットにおける音波発生機構の研究(噴流,後流および剥離流れの流動解析と応用(その1))

抄録

The three-dimensional time dependent compressible Navier-Stokes equations are numerically solved to study acoustic emission mechanism in a supersonic plane jet at high convective Mach numbers using high-order compact upwind schemes. Three cases for convective Mach number Mc=1.17 are presented. The first case is the jet flow forced randomly. The second case is the jet forced by random disturbances and two pair of most unstable oblique modes with a subsonic phase speed. The third case is the jet forced by random disturbances, two pairs of most unstable oblique modes and a pair of subharmonic oblique modes. The numerical results provide new physical insights into three-dimensional structures and acoustic wave generation mechanisms in a plane turbulent jet. Upstream disturbance conditions play an important role for the evolution of the jet flow structures. The numerical results show that the jet meandering is suppressed in the jet forced by oblique modes. Therefore, the intense sound radiation observed in the randomly forced jet can be reduced by forcing with a pair of oblique modes.