圆环管道中曲率对流动稳定性的影响

为了研究圆环管道中曲率对流动稳定性的影响，选取了展向带有曲率的轴向流动和轴向带有曲率的周向流动两种圆环管道模型进行分析.采用线性稳定性理论分别计算了两种模型下不同曲率的稳定性和扰动演化情况，并和槽道流进行比较，从而得到了曲率对基本流动、特征值和特征函数的影响.结果表明：曲率越大，基本流向内侧偏转越大，扰动波流向波数越大，增长率越小，中性曲线的不稳定区域越小，特征函数的对称性越差.因此曲率对边界层内的扰动起着稳定的作用，并且在一定范围内曲率越大，稳定性越好.

Influence of curvature on flow stability in circular pipe

In order to research the influence of curvature on flow stability in circular pipe, two circular pipe models of axial flow of spanwise curvature and circumferential flow of axial curvature were studied. For two models, the stabilities and disturbance evolutions of difference curvatures were calculated by the linear stability theory. And the results were compared with channel flow. Then the influences of curvature on basic flow, eigenvalue and eigenfunction were obtained. Result showed that, along with the greater curvature, the basic flow would deflect inside, the axial wavenumber of disturbance wave became greater, the growth rate changed smaller, the unstable region of neutral curve diminished and symmetry of eigenfunction got worse. So curvature has a stabilizing influence on disturbances in boundary layers and the stability will be better when the curvature increases gradually in certain rang.