压力梯度对边界层两相流动稳定性的影响

分析了有压力梯度的边界层两相流动稳定性,推导出类似于Saffman理论的修正的稳定性方程,数值计算采用高精度的谱方法。结果说明,压力梯度对边界层两相流动稳定性有显著的影响,顺压梯度增强流动稳定性,而逆压梯度则促进流动失稳。在不同的压力梯度和浓度下,Stokes数对流动稳定性的影响是一致的,存在一个临界Stokes数,小Stokes数促进流动失稳,而大Stokes数则提高临界雷诺数,抑制流动失稳的最佳Stokes数为10的量级。

Boundary Layer Stability for two Phase Flow with Pressure Gradient

Linear stability of dusty-gas flow in a boundary layer with non-zero pressure gradient over a flat plate is investigated.The equations for the disturbances of gas and dust flows are reduced to a modified Orr-Sommerfeld equation similar to that obtained by Saffman,and the spectral method is adopted to simulate the procedare.The pressure gradient observably affects the hydrodynamic stability.A favorable pressure gradient stabilizes the flow while an adverse pressure gradient in duces unstable flow.For various pressure gradient and particle concentration,the effect of Stokes number is consistent qualitatively.A critical Stokes number(approaching to 1) exists to reveal that for various pressures and concentrations the addition of fine particles(St<1) reduces the critical Reynolds number while the coarse particles(St>1) stabilizes the boundary layer flow.For large Stokes number the stabilizing effect of particles is directly proportional to the particle concentrations,and vice versa for small Stokes numbers.The favorable Stokes numbers is of order 10.