Lagrangian block simulation of buoyancy at turbulence interfaces

Abstract

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.

Simulations of turbulent interfaces produced by positive and negative buoyancy are conducted by moving blocks of fluid in the direction of the flow. The second moment of the blocks increases at a rate proportional to the diffusivity. The block simulation is free of numerical oscillations. Unlike most classical methods, the error associated with Lagrangian block simulation is not cumulative. Artificial diffusion error is negligible. The non-diffusive Lagrangian block simulations have provided reliable data to evaluate the performance of (i) sub-grid scale modelling and (ii) K-ε modelling of turbulent flow under the opposing influence of buoyancy.