论文标题

使用有效模型在粗糙表面上预测阻力组件

Prediction of drag components on rough surfaces using effective models

论文作者

Jain, Sahaj, Sudhakar, Y.

论文摘要

由于多尺寸的性质以及随之而来的高计算成本与在粗糙表面上的流量模拟相关的高计算成本,因此正在开发有效模型,作为处理此类流量的实际手段。现有的有效模型主要集中于使用滑动长度准确预测界面速度。此外,它们主要关注平坦的接口,并且不直接解决阻力计算。在这项工作中,我们在极坐标中制定了蒸腾抗性模型,并解决了在粗糙表面上计算阻力组件的挑战。像滑动长度一样,我们引入了两个构成参数,称为剪切和压力校正因子,其中包含有关如何将总阻力分配到粘性和压力组件的信息。这些非经验参数的计算不必解决其他显微镜问题。它们可以从用于滑动长度计算的相同显微镜问题中获得。我们证明了提出的参数在粗糙表面上流动的参数的有效性。此外,以粗糙圆柱体上的流量为例,我们通过将有效模型结果与从几何形状分辨的模拟获得的有效模型结果进行比较,介绍了预测界面速度和阻力组件的准确性。本文提供的数值模拟证明,我们可以使用建议的本构参数准确地捕获粘性和压力在粗糙表面上拖动,以解决平坦和圆形接口问题。

Owing to the multiscale nature and the consequent high computational cost associated with simulations of flows over rough surfaces, effective models are being developed as a practical means of dealing with such flows. Existing effective models focus primarily on accurately predicting interface velocities using slip length. Moreover, they are concerned mainly with flat interfaces and do not directly address the drag computation. In this work, we formulate the Transpiration-Resistance model in polar coordinates and address the challenge of computing drag components on rough surfaces. Like slip length, we introduce two constitutive parameters called shear and pressure correction factors that encompass information about how the total drag is partitioned into viscous and pressure components. Computation of these non-empirical parameters does not necessitate solving additional microscale problems; they can be obtained from the same microscale problem used for the slip-length calculation. We demonstrate the effectiveness of the proposed parameters for the Couette flow over rough surfaces. Moreover, using the flow over a rough cylinder as an example, we present the accuracy of predicting interface velocity and drag components by comparing the effective model results with those obtained from geometry-resolved simulations. Numerical simulations presented in this paper prove that we can accurately capture both viscous and pressure drag over rough surfaces for flat- and circular-interface problems by using the proposed constitutive parameters.

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