第三ヘリカルモードペアによりマッハ波が抑制された超音速ジェットの音波放射特性

抄録

The three-dimensional compressible Navier-Stokes equations are numerically solved to study suppress Mach wave emission in a supersonic round jet at high Mach number using high-order compact upwind schemes. Two cases of inlet disturbance for Mach number M_j=2.0 are presented. The first case is the jet flow forced randomly. The second case is the jet forced by random disturbances and a pair of unstable 3rd helical modes (m=±3) with a subsonic phase speed. The numerical results show that the jet potential core region is reduced in the jet forced by a pair of 3rd helical modes. Therefore, the intense Mach wave radiation observed in the randomly forced jet can be reduced by forcing with a pair of 3rd helical modes.