水下航行体壁面脉动压力的大涡模拟研究

湍流壁面脉动压力是重要的水动力噪声源,开展相应的计算与试验研究十分必要。作者在大涡模拟的理论框架下,结合精细网格生成技术,对于水下航行体的壁面脉动压力进行了数值预报。首先,详细描述了所使用的大涡模拟方程与动态Smagorinsky亚格子模型,介绍了离散求解的数值方法。其次,利用大涡模拟计算了SUBOFF模型主体与附体上的表面压力分布,并利用试验结果进行了验证,分析了大涡模拟方法计算定常流动的可靠性。再次,计算了平板的湍流壁面脉动压力,并与CSSRC的消音风洞试验结果进行了对比,分析了大涡模拟方法计算非定常流动的可靠性。最后,对于水下航行体模型主体上三个位置与围壳上四个位置处的壁面脉动压力进行了大涡模拟,得到了脉动压力1/3OCT频谱,分析了频谱高频与低频特性以及衰减特性,并用试验结果进行了验证。研究表明,本文建立的水下航行体壁面脉动压力的数值预报方法是可靠的。

Large eddy simulation of wall pressure fluctuations of underwater vehicle

Wall pressure fluctuation beneath a turbulent boundary layer is an important source of hydrodynamic noise. It is necessary to carry out computational and experimental research. The wall pressure fluctuations of an underwater vehicle are numerically predicted under the theoretical framework of large eddy simulation (LES) with fine grid generated technique. Firstly, the equations of LES, the dynamic Smagorinsky subgrid model and numerical approach for discretization are described in details. Secondly, the pressure distribution on hull and appendages of SUBOFF model are computed by LES and validated by measured data. The robustness of LES in steady flow calculation is analyzed. Thirdly, the wall pressure fluctuations of a plate are computed and compared with experimental results of Small Anechoic Flow Facility in CSSRC. And the robustness of LES in unsteady flow calculation is analyzed. Finally, the wall pressure fluctuations on the hull (3 positions) and sail (4 positions) of an underwater vehicle are simulated by LES. The I/3 OCT spectrum are given. The frequency and decay characteristics of the spectnims are studied. The computed results are validated by experimental results. It shows that the numerical prediction method in the paper is credible.