Abstract
The presence of buoyancy forces due to stratification has a substantial effect on the flow development and mixing processes and hence influences the distribution of pollutants and suspended matter in environmental flows such as in reservoirs, lakes, and estuaries. In this study, we focus on the implementation and testing of proposed changes that explicitly account for buoyancy effects in Reynolds-averaged Navier-Stokes (RANS) turbulence models. Direct numerical simulation (DNS) data of stably stratified homogeneous turbulence are used to study the parameters in two-equation RANS turbulence models such as the buoyancy parameter Cε3, and the turbulent Prandtl number Prt in the k-ε model. Both the gradient Richardson number Ri = N2/S2, where N is the Brunt-Väisälä (or buoyancy) frequency and S = du/dz is the mean shear rate, and the turbulent Froude number Frk = ε/(Nk), where ε is the turbulent kinetic energy dissipation rate and k is the turbulent kinetic energy, are used as correlating parameters to characterize stratification in the k-ε model. We show that it may be more appropriate to use Frk as the parameter of choice for modeling the stratification parameters in the k-ε model since it is based on the local properties of the turbulence as opposed to Ri, which is a mean property of the flow. The proposed modifications were implemented in a one-dimensional water column model called the General Ocean Turbulence Model (GOTM) and used to simulate stably stratified channels flows. The results from numerical simulations using the modified k-ε model are compared to stably stratified channel flow DNS data to assess its efficacy. © 2011 ASCE.
Recommended Citation
Z. A. Elliott and S. K. Venayagamoorthy, "Implementation and Testing of RANS Turbulence Models for Stably Stratified Flows," World Environmental and Water Resources Congress 2011 Bearing Knowledge for Sustainability Proceedings of the 2011 World Environmental and Water Resources Congress, pp. 2156 - 2165, American Society of Civil Engineers, Jul 2011.
The definitive version is available at https://doi.org/10.1061/41173(414)225
Department(s)
Civil, Architectural and Environmental Engineering
Keywords and Phrases
Stratified flow; Turbulence
International Standard Book Number (ISBN)
978-078441173-5
Document Type
Article - Conference proceedings
Document Version
Citation
File Type
text
Language(s)
English
Rights
© 2025 American Society of Civil Engineers, All rights reserved.
Publication Date
21 Jul 2011
