LOW-REYNOLDS-NUMBER KAPPA-EPSILON MODELING WITH THE AID OF DIRECT SIMULATION DATA

The constant C(mu) and the near-wall damping function f(mu) in the edd y-viscosity relation of the k-epsilon model are evaluated from direct numerical simulation (DNS) data for developed channel and boundary-lay er flow, each at two Reynolds numbers. Various existing f(mu) model fu nctions are compared with the DNS data, and a new function is fitted t o the high-Reynolds-number channel flow data. The epsilon-budget is co mputed for the fully developed channel flow. The relative magnitude of the terms in the epsilon-equation is analysed with the aid of scaling arguments, and the parameter governing this magnitude is established. Models for the sum of all source and sink terms in the epsilon-equati on are tested against the DNS data, and an improved model is proposed.