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发展了一种模拟固壁近旁轴对称Stokes流中粘性液滴的运动和变形及直接计算固壁上应力的边界积分方法.用此方法对不同的液滴_固壁初始相对间距、粘度比、表面张力和浮力联合参数以及环境流动参数情况进行了数值实验.数值结果显示,由于环境流动和浮力的作用,随着时间的推进,液滴在轴向压缩,在径向拉伸.当环境流动的作用弱于浮力作用时,随着时间的推移,液滴上升并向上弯,固壁上由液滴运动所引起的应力不断减小.当环境流动的作用强于浮力作用时,随着时间的推移,液滴变得越来越扁.在这种情形,当大初始间距时,壁面上的应力随液滴的演变而增大;当小初始间距时,由环境流动、浮力及壁面对流动的较强作用的联合影响,此应力随液滴的演变而减小.由于液滴运动所引起的壁面应力的有效作用仅限于对称轴附近的一个小范围内,且此范围随液滴与固壁的初始间距增大而增大.应力的大小随初始间距增大而大为减小.表面张力对液滴变形有阻止作用.液滴粘性会减小液滴的变形和位置迁移.
A new boundary integral method was developed to simulate the motion and deformation of viscous liquid droplets in the Axisymmetric Stokes flow near the solid wall and to directly calculate the stress on the solid wall.Using this method, Numerical simulation results show that due to the environmental and buoyancy effects, the droplets are compressed in the axial direction and stretched in the radial direction as time goes by. As the environment flows Is weaker than the buoyancy effect, as the time goes by, the droplet rises and turns upward, the stress caused by the droplet motion on the solid wall decreases continuously.When the environmental flow is stronger than the buoyancy effect, The droplet becomes more and more flat. In this case, the stress on the wall increases with the droplet’s evolution when the initial spacing is large; when the initial spacing is small, the flow from the environment, the buoyancy and the wall pair The combined effect of the strong action of the flow, the stress decreases with the droplet evolution.Due to the effective role of the wall stress caused by droplet movement is limited to a small range near the axis of symmetry, and this range with the droplet and Solid wall The initial spacing increases and increases.The size of the stress decreases greatly with the increase of the initial spacing.The surface tension prevents the droplet deformation.The droplet viscosity will reduce the deformation and the position migration of the droplet.