Explicit algebraic models for stratified flows

Authors: Lazeroms, W.M.J., Brethouwer, G.B., Wallin, S.W., Johansson, A.V.J.
Document Type: Conference
Pubstate: Published
Journal: Proc 9th Int. ERCOFTAC Symposium on Engineering Turbulence Modeling and Measurements (ETMM9), Thessaloniki, Greece, Jun. 6-8 (2012)
Year: 2012


An explicit algebraic Reynolds stress and scalar flux model for stratified turbulent flows is formed from a coupled set of algebraic equations for the Reynolds stress anisotropy and the scaled scalar flux. The complete model is derived for two-dimensional mean flows, and evaluated for two test cases: turbulent channel flow and homogeneous shear flow, both with stable stratification. The channel flow results are compared with DNS data, and show a good agreement in the mean profiles, the Reynolds stress and the wall-normal scalar flux. The homogeneous shear flow case results in a critical gradient Richardson number close to 0.25. The derived model can thus correctly capture the effect of stable stratification on a turbulent shear flow.