What is it about?
Over the years, a broad set of subgrid-scale (SGS) models has been developed in large eddy Simulations (LESs). Eddy-viscosity models are potentially fully dissipative and do not permit backscatter. Recently, a new family of SGS models, termed as gradient-based models, has been introduced to calculate the SGS stresses in LES. In the present work, the MGM was implemented in the OpenFOAM package, and the pimpleFoam solver was improved to be adopted with non-eddy viscosity models.
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Why is it important?
We simulate a turbulent channel flow at the three different frictional Reynolds numbers of 180, 395 and 590 to evaluate the accuracy of the MGM along with the modified pimpleFoam solver. Furthermore, the results were compared with direct numerical simulation data and three eddy-viscosity models. In most of the profiles, MGM produced negligible errors and successfully followed the DNS data. The MGM reported a lower computational cost compared to the DSM and the efficiency could become more pronounced if Reynolds number increases.
Perspectives
This study has been concerned with the development of gradient-based non-linear SGS models and their a-posteriori evaluation in turbulent channel flow. I hope this article makes gradient-based models regain their popularity and with reduction of computational time and improvement of simulation accuracy, a huge evolution in industries related to turbulent flows is feasible.
Elyas Larkermani
NTNU: Norwegian University of Science and Technology
Read the Original
This page is a summary of: Evaluating the modulated gradient model in large eddy simulation of channel flow with OpenFOAM, Journal of Turbulence, June 2018, Taylor & Francis,
DOI: 10.1080/14685248.2018.1483078.
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