Gravitational settling of solid particles through density interfaces is studied numerically when at least one of the fluids is non-Newtonian. The Carreau–Yasuda model is used to model the shear-thinning behavior of the non-Newtonian fluid. The coupled level-set and volume-of-fluid method is used to track the interface between the two fluids. It is found that the presence of shear-thinning fluids significantly affects the settling dynamics of solid spheres. For lower power index, the lighter fluid is more entrained by the sphere into the denser fluid. It is revealed that the sphere velocity after impacting the interface increases with the power index, density ratio and buoyancy jump. The shear-thinning effect of the upper and lower non-Newtonian fluids is quite noticeable and the motion of the solid sphere before crossing the interface is different to the case of Newtonian fluids. For the case of upper Newtonian fluid, there is a smaller resistance force at the interface, which c...

中文翻译：

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非牛顿效应对固体颗粒沉降过程的影响

当至少一种流体是非牛顿流体时，通过密度界面对固体颗粒的重力沉降进行了数值研究。Carreau–Yasuda模型用于对非牛顿流体的剪切稀化行为进行建模。水平集和流体体积的耦合方法用于跟踪两种流体之间的界面。发现剪切稀化流体的存在显着影响固体球的沉降动力学。对于较低的功率指数，较轻的流体被球体更多地夹带到较稠密的流体中。结果表明，撞击界面后的球速随功率指数，密度比和浮力跳跃而增加。上部和下部非牛顿流体的剪切稀化效果非常明显，并且在穿过界面之前，固体球体的运动与牛顿流体的情况不同。对于较高的牛顿流体，在界面处有较小的阻力，这会导致...