双向耦合点粒子模拟的一种通用速度修正方案
A general velocity correction scheme for two-way coupled point-particle simulations
摘要：
在含颗粒流体流动模拟中采用的欧拉-拉格朗日点粒子模型的准确性取决于通过闭合模型对颗粒力的准确估计。典型的力闭合模型需要计算颗粒位置处的滑移速度，这又需要准确估计未扰动流体速度。然而，当流体和颗粒相是双向耦合的流体速度场被颗粒的存在所干扰。通常的做法是使用扰动速度来计算颗粒力，这可能导致预测颗粒动力学的误差高达100%。在这项工作中，一个通用的速度校正方案的开发，有利于准确估计的未受干扰的流体速度在颗粒负载的流体流动和无滑壁。该模型可以处理不同尺寸的颗粒，任意插值函数，具有大纵横比的各向异性网格，以及有壁流动。本修正方案的动机是Esmaily和Horwitz（JCP，2018）最近对无界颗粒流的研究。壁有界的流动所需的修改开发，以便在任何壁距离的不受干扰的流体速度准确地恢复，渐近接近无界计划远离墙壁的颗粒。详细的一系列验证试验进行了平行和垂直运动的颗粒的无滑移壁的沉降速度。一系列的流动参数和网格配置，涉及各向异性网格的纵横比通常遇到的颗粒负载的湍流槽道流，被详细考虑。当考虑壁面效应时，与无界修正方案相比，本修正方案将预测近壁粒子运动的误差减小了一个数量级。
英文摘要：
The accuracy of Euler-Lagrange point-particle models employed in particle-laden fluid flow simulations depends on accurate estimation of the particle force through closure models. Typical force closure models require computation of the slip velocity at the particle location, which in turn requires accurate estimation of the undisturbed fluid velocity. However, when the fluid and particle phases are two-way coupled the fluid velocity field is disturbed by the presence of the particle. A common practice is to use the disturbed velocity to compute the particle force which can result in errors as much as 100% in predicting the particle dynamics. In this work, a general velocity correction scheme is developed that facilitates accurate estimation of the undisturbed fluid velocity in particle-laden fluid flows with and without no-slip walls. The model can handle particles of different size, arbitrary interpolation functions, anisotropic grids with large aspect ratios, and wall-bounded flows. The present correction scheme is motivated by the recent work of Esmaily & Horwitz (JCP, 2018) on unbounded particle-laden flows. Modifications necessary for wall-bounded flows are developed such that the undisturbed fluid velocity at any wall distance is accurately recovered, asymptotically approaching the unbounded scheme for particles far away from walls. A detailed series of verification tests were conducted on settling velocity of a particle in parallel and perpendicular motions to a no-slip wall. A range of flow parameters and grid configurations; involving anisotropic grids with aspect ratios typically encountered in particle-laden turbulent channel flows, were considered in detail. When the wall effects are accounted for, the present correction scheme reduces the errors in predicting the near-wall particle motion by one order of magnitude smaller values compared to the unbounded correction schemes.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
