Residual Term of the Volume-Filtered Multiphase Flow Momentum Equation

作     者：Ni, Menglin 

作者单位：Iowa State University 

学位级别：M.S., Master of Science/Master of Surgery

导师姓名：Subramaniam, Shankar

授予年度：2022年

页      码：41页

主      题：Multiphase flow Particle resolved direct numerical simulation Volume-filtered Euler-Lagrange 

摘      要：Spatial filtering of multiphase flow equations results in the volume-filtered Euler-Lagrange (VFEL) method that can efficiently simulate large domains, and capture a wide range of scales including mesoscale structures corresponding to particle clustering. However, spatial filtering results in unclosed residual terms in the VFEL equations which need to be modeled. These have been modeled using ensemble-averaged models, such as the average drag on a particle in a suspension (Capecelatro(2013)) for the residual filtered interphase momentum exchange term. Here we quantify the unclosed terms in the filtered momentum equation for a particle-laden suspension using particle resolved direct numerical simulation (PR-DNS). Using the indicator function approach we derive the exact interphase momentum exchange term, which differs slightly from the approximate expression given by Capecelatro (2013) for the interphase momentum exchange term that was based on simplifying assumptions of Anderson (1967). PR-DNS data from steady flow past a statistically homogenous particle assembly is filtered to quantify both exact and approximate versions of the interphase momentum exchange term for different filter widths. Analysis of the differences is used to provide insight into the range of validity of the existing deterministic model, and to provide direction for future scale-dependent stochastic models.