The focus of this work is on understanding the effect of water injection from the launch pad on the noise generated during rocket’s lift-off. To simplify the problem, we consider a supersonic jet impinging on a flat plate with water injection from the impingement plate. The Volume of Fluid model is adopted in this work to simulate the two-phase flow. A Hybrid Large Eddy Simulation – Unsteady Reynolds Averaged Simulation approach is employed to model turbulence, wherein Unsteady Reynolds Averaged Simulation is used near the walls, and Large Eddy Simulation is used elsewhere in the computational domain. The numerical issues associated with simulating the noise of two-phase supersonic flow are addressed. The pressure fluctuations on the impingement plate obtained from numerical simulations agree well with the experimental data. Furthermore, the predicted effect of water injection on the far-field broadband noise is consistent with that of the experiment. The possible mechanisms for noise reduction by water injection are discussed.

中文翻译：

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冲击垫注水抑制火箭发射噪声模拟

这项工作的重点是了解从发射台注水对火箭升空过程中产生的噪音的影响。为简化问题，我们考虑一个超音速射流撞击平板，并从撞击板上注入水。本文采用流体体积模型来模拟两相流动。混合大涡模拟 - 非定常雷诺平均模拟方法用于模拟湍流，其中非定常雷诺平均模拟用于壁附近，而大涡模拟用于计算域的其他地方。解决了与模拟两相超声速流动噪声相关的数值问题。从数值模拟中获得的冲击板上的压力波动与实验数据非常吻合。此外，注水对远场宽带噪声的预测效果与实验一致。讨论了通过注水降低噪声的可能机制。