Correction scheme for point-particle models applied to a nonlinear drag law in simulations of particle-fluid interaction
Correction scheme for point-particle models applied to a nonlinear drag law in simulations of particle-fluid interaction
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DOI：
10.1016/j.ijmultiphaseflow.2018.01.003
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发表时间：
2018-04-01
影响因子：
3.8
通讯作者：
Mani, A.
中科院分区：
文献类型：
--
作者：
Horwitz, J. A. K.;Mani, A.
流体中颗粒的阻力定律通常用未受扰动的流体速度来表示，未受扰动的流体速度定义为颗粒在流体中产生扰动之前所看到的流体速度。在双向耦合点粒子模拟中，来自未扰动状态的信息是不可用的，并且必须使用扰动速度场来近似。（[Horwitz，J. A. K. & Mani，A. 2016双向耦合流中点粒子跟踪的斯托克斯阻力精确计算。Journal of Computational Physics 318，85-109]）最近开发了一种方法来估计在低雷诺数下运动并遵守线性斯托克斯阻力定律的颗粒的未扰动速度。使用这种校正，数值模拟的收敛性被证明与一系列规范设置的预期物理行为相匹配。在本文中，我们研究这种修正方案的颗粒在有限雷诺数下移动，考虑非线性Schiller-Naumann阻力定律。我们的研究结果表明，线性校正可以显着提高预测的阻力颗粒雷诺数约为10。此外，我们提出了一个调查的影响时，施加到模拟强制均匀湍流颗粒负载流，以进一步证明建模的重要性，未受干扰的流体速度的校正。虽然粒子加速度和雷诺数的形状pdf不敏感的未受干扰的流体速度校正，我们表明，未校正的计划可能会导致显着的平均粒子雷诺数和粒子加速度的标准偏差预测不足。此外，粒子径向分布函数的检查揭示了适当的增强，在优先浓度预测的校正方案（St > 1）。我们的研究表明，湍流的未扰动的流体速度校正是更重要的颗粒尺寸较大，而斯托克斯数的依赖性是更复杂的。修正过程表明，在较高的Stokes数，颗粒滑移速度的差异较大，但在较低的Stokes数的优先浓度增强。最后，我们提出了一个政权图，以指导点粒子模拟方案的选择。(C)2018爱思唯尔有限公司版权所有
Drag laws for particles in fluids are often expressed in terms of the undisturbed fluid velocity, defined as the fluid velocity a particle sees before its disturbance develops in the fluid. In two-way coupled point particle simulations the information from the undisturbed state is not available and must be approximated using the disturbed velocity field. ([Horwitz, J. A. K. & Mani, A. 2016 Accurate calculation of stokes drag for point-particle tracking in two-way coupled flows. Journal of Computational Physics 318, 85-109]) recently developed a procedure to estimate the undisturbed velocity for particles moving at low Reynolds number and obeying the linear Stokes drag law. Using this correction, convergence of numerical simulations was demonstrated to match the expected physical behavior for a range of canonical settings. In this paper we examine this correction scheme for particles moving at finite Reynolds number, by considering the nonlinear Schiller-Naumann drag law. Our results indicate that a linear correction can significantly improve prediction of drag force up to particle Reynolds number of about 10. Additionally, we present an investigation of the impact of this correction when applied to simulations of forced homogeneous turbulent particle-laden flows to further demonstrate the importance of modelling the undisturbed fluid velocity. While the shapes of particle acceleration and Reynolds number pdfs are not sensitive to correcting for the undisturbed fluid velocity, we show that an uncorrected scheme can result in significant under-prediction of the mean particle Reynolds number and standard deviation of particle acceleration. Furthermore, examination of particle radial distribution function reveals modest enhancements in preferential concentration predicted by the correction scheme (for St > 1). Our investigations of turbulent flows indicate the undisturbed fluid velocity correction to be more important for particles with larger size, while the Stokes number dependence is more complicated. The correction procedure shows a greater difference in particle slip velocity at higher Stokes numbers but more enhancement in preferential concentration at lower Stokes numbers. Finally, we propose a regime diagram to guide scheme selection for point-particle modelling. (C) 2018 Elsevier Ltd. All rights reserved.