Variational Multiscale Large Eddy Simulations of Rayleigh-Bénard Convection at High Ra
Abstract
Large eddy simulations (LES) of two- and three-dimensional Rayleigh-Bénard convection are performed up to Ra =1014 for Pr = 1 and Pr = 7 . These simulations are performed using novel LES models based on the variational multiscale (VMS) formulation. The new model is presented as a mixed model which combines the VMS formulation for Rayleigh-Bénard convection with an eddy viscosity model (EVM) to capture the effects of the Reynolds stresses in high Ra convection. In the present work, the Wall-Adapting Local Eddy-viscosity (WALE) model is used as the EVM. The new models were implemented in the finite element code Drekar and simulations were performed using continuous, piecewise linear finite elements. The two dimensional simulations were performed in a domain with aspect ratio 2 while the three-dimensional simulations were performed in a cylinder of aspect ratio 1 / 4 . Least squares fits to the Nu - Ra data show Nu2D = 0 . 127 Ra 0 . 284 and Nu3D = 0 . 104 Ra 0 . 310 .
- Publication:
-
APS Division of Fluid Dynamics Meeting Abstracts
- Pub Date:
- 2020
- Bibcode:
- 2020APS..DFDT01013S