均匀流中声学速度预测的时域解析公式

Time-domain analytical formulation for acoustic velocity prediction in uniform mean flow

  • 摘要: 采用理论解析和数值计算方法研究均匀流中声学速度预测的时域解析公式。对基于可渗透面原理的声学速度预测,理论分析了对流矢量波动方程的右端源项,结果显示部分对声学速度传播有贡献的可渗透面源被忽略。基于对流矢量波动方程时域积分公式V1A-M,进一步考虑丢失可渗透面源的贡献,发展了解析公式CV1A-M。对均匀平均流中静止与旋转的单极子和偶极子,利用公式V1A-M和CV1A-M数值预测了点源辐射的声学速度。公式CV1A-M数值解与理论值吻合一致,公式V1A-M因可渗透面载荷源部分丢失,数值解与理论值差异明显。均匀流中偶极子点源声辐射不会诱发涡波扰动,线化欧拉方程能够描述声学速度与声学压力间关系。

     

    Abstract: The time-domain analytical formulation for acoustic velocity prediction in a uniform mean flow is considered theoretically and numerically. For acoustic velocity prediction based on the permeable surface principle, a theoretical analysis of the source terms on the right hand of the convective vector wave equation shows that part of the permeable surface source contributing to the acoustic velocity propagation is neglected. Based on the time-domain integral formulation V1A-M for the convective vector wave equation, an analytical formulation CV1A-M is developed by further considering the contribution from the missing permeable surface source. The acoustic velocity radiations are predicted numerically using formulations V1A-M and CV1A-M for a stationary/rotating monopole and dipole in a uniform mean flow. The numerical solutions of formulation CV1A-M agree well with the theoretical values, while the numerical solutions of formulation V1A-M differ significantly from the theoretical values due to the neglection of part of the loading source on the permeable surface. The radiation from a dipole in a uniform mean flow dose not induce any vortical disturbance and the linearised Euler equation can be used to describe the relationship between acoustic velocity and acoustic pressure.

     

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