A Nonlinear Low-Reynolds-Number k -$\varepsilon$ Model for Turbulent Separated and Reattaching Flows

난류박리 및 재부착 유동의 해석을 위한 비선형 저레이놀즈수 k -$\varepsilon$ 난류모형의 개발

An improved version of nonlinear low-Reynolds-number k-.epsilon. model is developed. In this model, the limiting near-wall behavior and nonlinear Reynolds stress representations are incorporated. Emphasis is placed on the adoption of Ry(.iden. $k^{1}$2/y/.nu.) instead of $y^{[-10]}$ (.iden. $u_{{\tau}/y/{\nu}}$) in the low-Reynolds-number model for predicting turbulent separated and reattaching flows. The non-equilibrium effect is examined to describe recirculating flows away from the wall. The present model is validated by doing the benchmark problem of turbulent flow behind a backward-facing step. The predictions of the present model are cross-checked with the existing measurements and DNS data. The model performance is shown to be generally satisfactory.