Campus Units

Chemical and Biological Engineering

Document Type

Article

Research Focus Area

Computational Fluid Dynamics

Publication Version

Published Version

Publication Date

11-12-2020

Journal or Book Title

Physics of Fluids

Volume

32

Issue

11

First Page

115118

DOI

10.1063/5.0030092

Abstract

In the context of modeling turbulent scalar mixing using probability density function (PDF) methods, the treatment of molecular mixing is of paramount importance. The conditional moment closure (CMC) offers a high-fidelity description for molecular mixing in nonpremixed flows. Recent work has demonstrated that first-order CMC can be implemented numerically using the moments of the conditioning variable and first-order joint moments of the scalar of interest. When solving the CMC using, for example, quadrature-based moment methods (QBMM), a functional form must be chosen for the conditional scalar dissipation rate (CSDR) of the conditioning variable. In prior work, the CSDR was chosen to produce a β-PDF for the conditioning variable (mixture fraction) at steady state. This choice has the advantage that the system of moment equations used in QBMM-CMC can be written in closed form. In this work, an alternative choice for the CSDR is investigated, namely, the amplitude mapping closure (AMC). With the AMC, the moment equations can be closed using the quadrature method of moments incorporated into a realizable ordinary differential equation solver. Results are compared with the β-CSDR closure for binary, passive scalar mixing in homogeneous single- and disperse-phase turbulent flows. It is also demonstrated that the moment formulation of CMC provides a straightforward method for modeling the effect of differential diffusion in the context of CMC.

Comments

This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Fox, Rodney O. "Effect of the conditional scalar dissipation rate in the conditional moment closure." Physics of Fluids 32, no. 11 (2020): 115118 and may be found at DOI: 10.1063/5.0030092. Posted with permission.

Copyright Owner

The Author(s)

Language

en

File Format

application/pdf

Available for download on Friday, November 12, 2021

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