Time-Averaged Active Model-Split Hybrid RANS/LES

Event Sponsor: 
Computational Sciences Division Seminar
Start Date: 
Feb 4 2019 - 2:30pm
Building 240/Room 4301
Argonne National Laboratory
Sigfried Haering
Speaker(s) Title: 
University of Texas
Ramesh Balakrishnan

Eddy-resolving methods capable of transitioning through arbitrary levels of modeled and resolved turbulence have the potential to ameliorate both RANS deficiencies and LES expense enabling both computationally feasible and reliably predictive simulation of complex flows. However, hybrid RANS/LES approaches have led to a host of unique complications in addition to pre-existing RANS and LES issues. This work proposes a framework aimed at overcoming such challenges. Expanding on the two-velocity method [1], the model is split into separate portions primarily responsible for providing either the stress or resolve d dissipation while obviating blending functions. The model-split approach both reduces the physics-approximation burden on eddy viscosities and provides model selection flexibility. Additionally, fluctuations are continually generated at the smallest locally resolved scales thereby driving the system towards grid-resolved LES while maintaining or improving the total turbulent stress. The model is demonstrated on fully-developed, incompressible channel flow and shown to be promising.

1] J. Uribe, N. Jarrin, R. Prosser, and D. Laurence, "Development of a two-velocities hybrid RANS-LES model and its application to a trailing edge flow," Flow Turbulence Combust, vol. 85, pp. 181–197, 2010.

Miscellaneous Information: 

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