论文标题
从可压缩边界层产生的马赫波辐射产生的基于分解的观点
A resolvent-based perspective on the generation of Mach wave radiation from compressible boundary layers
论文作者
论文摘要
我们确定了分别放大从基于线性的Navier-Stokes模型获得的强迫机制，这些机制分别放大了可压缩平行边界层的模型。分解分析用于分析线性模型，其中线性方程式的非线性项充当对线性项的强迫。考虑亚音速模式，只有强迫到动量方程的螺线管成分放大了这些模式。在考虑超音速模式时，我们发现这些是辐射到自由度的压力波动。在自由度中，这些模式紧随无粘性马赫波的趋势。 There are two distinct forcing mechanisms that amplify the supersonic modes: (i) the 'direct route' where the forcing to the continuity and energy equations and the dilatational component of the forcing to the momentum equations directly force the mode and (ii) the 'indirect route' where the solenoidal component of the forcing to the momentum equations force a response in wall-normal velocity, and this wall-normal velocity in-turn forces the超音速模式。大多数超音速模式都被直接路线强迫。但是，当考虑到直接数值模拟中的马赫波从流量的缓冲层强迫时，强迫的间接路线变得很重要。我们发现这些观察结果也适用于流向发展的边界层。这些结果与文献中有关可压缩湍流壁结合的流量中速度的电磁和扩张成分的观察结果是一致的，并扩展了观察结果。
We identify forcing mechanisms that separately amplify subsonic and supersonic features obtained from a linearized Navier-Stokes based model for compressible parallel boundary layers. Resolvent analysis is used to analyse the linear model, where the non-linear terms of the linearized equations act as a forcing to the linear terms. Considering subsonic modes, only the solenoidal component of the forcing to the momentum equations amplify these modes. When considering supersonic modes, we find that these are pressure fluctuations that radiate into the freestream. Within the freestream, these modes closely follow the trends of inviscid Mach waves. There are two distinct forcing mechanisms that amplify the supersonic modes: (i) the 'direct route' where the forcing to the continuity and energy equations and the dilatational component of the forcing to the momentum equations directly force the mode and (ii) the 'indirect route' where the solenoidal component of the forcing to the momentum equations force a response in wall-normal velocity, and this wall-normal velocity in-turn forces the supersonic mode. A majority of the supersonic modes considered are dominantly forced by the direct route. However, when considering Mach waves that are, like in direct numerical simulations, forced from the buffer layer of the flow, the indirect route of forcing becomes significant. We find that these observations are also valid for a streamwise developing boundary layer. These results are consistent with, and extend the observations in the literature regarding the solenoidal and dilatational components of velocity in compressible turbulent wall-bounded flows.
