Effects of uniform injection at the wall on the stability of Couette-like flows
Effects of uniform injection at the wall on the stability of Couette-like flows
复制标题
壁面均匀喷射对库埃特流稳定性的影响
DOI：
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发表时间：
1997
期刊：
影响因子：
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通讯作者：
J. Angilella
中科院分区：
文献类型：
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作者：
F. Nicoud;J. Angilella
对一族近乎平行的下壁注水、上壁吸力的附壁弓进行了线性稳定性分析。平均压力梯度是这样的，即使在注入的情况下，流向速度分布仍然保持线性。渐近分析表明，对于弱注入，线性扰动的扩张率是注入雷诺数(基于区域宽度和注入速度)的线性函数。这一点得到了数值求解器的证实，数值求解器还表明，由于注入过程，本征模在复平面内发生了剧烈的重组。特别是，本征值分布不再是对称的。此外，相速度的虚部趋于增大，使得一些模式可能变得线性不稳定，然而，只要注入雷诺数小于临界值48，基流就保持稳定。研究还发现，较高的喷射率(喷射雷诺数大于80)可以稳定弓形，就像已经在槽道或旋转流动中观察到的那样。
A linear stability analysis of a family of nearly parallel wall-bounded Bows with injection at the lower wall and suction at the upper one is presented. The mean pressure gradient is such that the streamwise velocity profile remains linear in spite of injection. An asymptotic analysis shows that, for weak injection, the expansion rate of linear perturbations is a Linear function of the injection Reynolds number (based on the width of the domain and the injection velocity). This point is confirmed by a numerical solver that also shows that, due to the injection process, the eigenmodes are drastically reorganized in the complex plane. In particular, the eigenvalue distribution is no longer symmetric. Moreover, the imaginary part of the phase velocity tends to increase so that some modes may become linearly unstable, However, the base flow remains stable as long as the injection Reynolds number is lower than a critical value dose to 48. It is also found that higher injection rates (injection Reynolds numbers greater than 80) stabilize the Bow, as already observed for channel or rotating flows.