Acoustic streaming in high-speed compressible channel flow and its impact on heat and momentum transfer is analysed numerically at two different Mach numbers, $M_{b}=0.75$ and 1.5, and moderate Reynolds numbers, $Re_{b}=3000$ and 6000. An external time-periodic forcing function is implemented to model the effect of acoustic drivers placed on the sidewalls. The excitation frequency is chosen according to the linear stability analysis of the background (unexcited) flow. High-fidelity numerical simulations performed at the optimal resonant condition reveal an initially exponential growth of perturbations followed by a nonlinear regime leading to the limit-cycle oscillations. In the last stage, we observe an acoustic (steady) streaming appearing as a result of nonlinear interactions between the periodic external wave and the background flow. This causes a steady enhancement in heat transfer at a rate higher than the skin-friction augmentation. We also show that perturbations of similar amplitude, but at suboptimal frequencies, may not lead to such limit-cycle oscillations and cannot make any noticeable modifications to the time-averaged flow quantities. The present research is the first study to demonstrate the acoustic streaming in compressible turbulent flows, and it introduces a novel technique towards enhancing the heat transfer with minimal skin-friction production.

中文翻译：

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用于增强传热的湍流可压缩通道流中的声流

在两个不同的马赫数 $M_{b}=0.75$ 和 1.5 以及中等雷诺数 $Re_{b}=3000$ 下对高速可压缩通道流中的声流及其对热和动量传递的影响进行了数值分析和 6000。实施外部时间周期强制函数来模拟放置在侧壁上的声学驱动器的效果。根据背景（未激发）流的线性稳定性分析选择激发频率。在最佳共振条件下进行的高保真数值模拟揭示了扰动的初始指数增长，然后是导致极限循环振荡的非线性状态。在最后阶段，我们观察到由于周期性外部波和背景流之间的非线性相互作用而出现的声学（稳定）流。这导致热传递以高于皮肤摩擦增加的速率稳定增强。我们还表明，类似幅度的扰动，但在次优频率下，可能不会导致这种极限循环振荡，并且不能对时间平均流量进行任何明显的修改。本研究是第一个证明可压缩湍流中的声流的研究，它引入了一种新技术，以最小的皮肤摩擦产生来增强传热。