Investigation of weakly-nonlinear development of unsteady Görtler vortices
Investigation of weakly-nonlinear development of unsteady Görtler vortices
复制标题
非定常戈特勒涡旋弱非线性发展的研究
DOI：
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发表时间：
2010
期刊：
影响因子：
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通讯作者：
D. Mischenko
中科院分区：
文献类型：
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作者：
A. Boiko;Andrey V. Ivanov;Y. Kachanov;D. Mischenko
我们从实验和理论上研究了凹面上边界层非定常(一般)Görtler不稳定性的弱非线性发展阶段。主要研究了非定常Görtler涡发展过程中的早期非线性现象，这种非定常Görtler涡属于稳定性问题离散谱中的第一个，也是增长最快的模式。我们研究了不稳定性随基模频率和初始扰动幅度的变化规律。发现非定常Görtler涡发展的弱非线性阶段表现出以下特征：(A)频率-波数谱中组合模之间的非线性相互作用，(B)扰动幅度和相位的壁法向轮廓的扭曲，(C)基本Görtler模和大多数组合模的增长率降低，以及(D)非定常扰动的相速度降低。结果表明，当基频波数模的幅值达到4-6%的阈值时，扰动进入弱非线性发展区，这个值远大于Tollmien-Schlichting波的值(1-2%)，但显著低于三维边界层中横流不稳定模的值(大于10%)。
We have examined, both experimentally (using fully controlled disturbances) and theoretically, the weakly-nonlinear development stages of unsteady (in general) Görtler instability of a boundary layer over a concave surface. Primary attention was given to early manifestations of nonlinearity in the development of unsteady Görtler vortices belonging to the first, most rapidly growing, mode in the discrete spectrum of the stability problem. We have investigated the manifestations of instability versus the frequency of the fundamental (primary) Görtler mode and the initial disturbance amplitude. The weakly-nonlinear stage of development of unsteady Görtler vortices was found to display the following characteristic features: (a) nonlinear interaction among the combination modes in the frequency-wavenumber spectrum, (b) distortion of the wall-normal profiles of disturbance amplitudes and phases, (c) reduction of the growth rate of the fundamental Görtler mode and the majority of combination modes, and (d) a decrease in the phase velocities of unsteady disturbances. It was found that the disturbances enter the region of weakly-nonlinear development after the amplitude of the fundamental frequency-wavenumber mode reaches a threshold of 4–6 %, this value being much greater than that for Tollmien — Schlichting waves (1–2 %) but significantly lower than that for the cross-flow instability modes in three-dimensional boundary layer (more than 10 %).
非自相似边界层中调制波共振相互作用的实验研究
DOI：
10.1007/978-90-481-3723-7_97
发表时间：
2010
期刊：
影响因子：
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作者：
I.B. de Paula;W. Würz;E. Krämer;V.I. Borodulin;Y.S. Kachanov
通讯作者：
Y.S. Kachanov