2ND-ORDER CORRECTIONS OF THE K-EPSILON-MODEL TO ACCOUNT FOR NONISOTROPIC EFFECTS DUE TO BUOYANCY

A new turbulence model which is a hybrid of the kappa-epsilon model and an algebraic Reynolds stress model (ASM) is developed. This model takes from an ASM that part of the non-isotropic Reynolds stress which is due to buoyancy, and the remaining part from the kappa-epsilon model. This concept is also applicable to flows with rotation where the Coriolis forces affect the turbulence by increasing its non-isotropy. Th model is tested in a buoyancy-driven cavity flow. The contributions from the ASM corrections to the Reynolds stress and the turbulent heat flux are up to five and ten times, respectively, larger than those from the kappa-epsilon model.