Abstract: To investigate the pressure pulsation characteristics of underwater supersonic jet flow field and the force characteristics on the floating mine， based on the VOF （Volume of fluid） multiphase flow model， a numerical model of supersonic gas jet under different working conditions（under-expansion， full-expansion， over-expansion） was established to study force characteristics on the floating mine. The results show that under the under-expansion condition， the thrust of the engine is gentle and the average thrust is about 12.2kN， and the force on the floating mine has never been negative. Under the full-expansion condition， the positon where necking and bulging of the gas jet occur is far away from the mine body， which weakens violently thrust oscillation of the engine and the vibration of the force on the shell of the floating mine. Under the over-expansion condition， the positon where necking and bulging of the gas jet occur is close to the nozzle， and the thrust of engine pulsates violently， generating 21.7% of the oscillation amplitude. When bulging occurs， the pressure in the flow field significantly reduces， which reduces the force on the rear body of the floating mine， and increases the resistance of the shell. The maximum negative thrust of the floating mine is 27kN.

Key words: Underwater solid rocket motor;Characteristics of thrust;Pressure oscillation;Breaking and bulging;Multiphase flow

摘要： 为了研究水下超声速喷射流流场压力脉动特性及其对上浮水雷的受力影响特性，基于VOF （Volume of fluid）多相流模型，建立了上浮水雷在不同工作状态（欠膨胀、完全膨胀、过膨胀）下的数值计算模型，研究了水下燃气喷射流对上浮水雷的受力特性影响。结果显示，欠膨胀工况时，发动机推力平缓，平均推力约为12.2kN，上浮水雷受力未出现负值；完全膨胀时，射流发生颈缩、胀鼓等现象的位置距离雷体较远，导致发动机推力及水雷壳体受力振荡不剧烈；过膨胀工况时，射流发生颈缩、胀鼓等现象的位置距离喷管较近，发动机推力发生剧烈脉动，产生21.7%的振荡幅度，胀鼓现象发生时，流场压力显著降低，使得上浮水雷后体受力减小，壳体阻力增大，上浮水雷最大产生27kN的负推力。

关键词: 水下固体火箭发动机;推力特性;压力脉动;颈缩与胀鼓;多相流