分布式粗糙度对马赫数为4.5的平板边界层稳定性的影响

发布时间：2019-03-19 19:07

【摘要】：采用数值模拟求解Navier-Stokes(N-S)方程的方法研究了小幅值分布式粗糙度对马赫数为4.5的平板边界层中扰动演化的影响.用泰勒展开线性化的办法将边界条件取在光滑平板壁面上,来模拟小幅值分布式粗糙度.研究了粗糙度及扰动的不同因素对边界层扰动演化的影响,其中包括粗糙度高度、波长、粗糙度区域的长度及扰动波频率等.研究结果表明:分布式粗糙度通过改变边界层基本流场影响扰动波的幅值演化,一定幅值的分布式粗糙度会使粗糙度区域前的不稳定区向低频移动,使粗糙度区域后的不稳定区向高频移动.从总体效果上看,对于通过粗糙度时,靠近中性曲线下支界相对低频的扰动,粗糙度会抑制其幅值的增长;对于靠近中性曲线上支界相对高频的扰动,粗糙度会促进其幅值的增长.
[Abstract]:The effect of small amplitude distributed roughness on the perturbation evolution in the boundary layer of the plate with Mach number is studied by numerical simulation for solving the Navier-Stokes (N\ +) equation. The small amplitude distributed roughness is simulated by using Taylor expansion linearization method and the boundary conditions are taken on the smooth plate wall. The effects of roughness and disturbance factors on the evolution of boundary layer disturbances, including roughness height, wavelength, the length of roughness region and the frequency of disturbance wave, are studied. The results show that the distributed roughness affects the amplitude evolution of disturbance wave by changing the basic flow field in the boundary layer, and the distributed roughness of certain amplitude will make the unstable region in front of the roughness region move to the low frequency. The unstable region after roughness region moves to high frequency. From the overall effect, the roughness will restrain the increase of amplitude for the disturbance of the relative low frequency near the lower branch boundary of the neutral curve when the roughness is passed. For the disturbance of relative high frequency near the upper branch of the neutral curve, the roughness will promote the increase of its amplitude.
【作者单位】：天津大学机械工程学院力学系;
【基金】：国家自然科学基金(11332007);国家自然科学基金青年基金(11202147) 高等学校博士学科点专项科研基金(20120032120007)
【分类号】：V211

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