Publisher : The Korean Society of Mechanical Engineers
DOI : 10.22634/KSME-B.19184.108.40.2065
Title & Authors
수정 k-ε 모델에 의한 실제 L-형 리블렛의 항력저감 성능예측 명현국;
A low-Reynolds-number k-ε turbulence model is applied to predict drag reduction performance for actual L-shaped (blade-type) riblets with finite-thickness in fully-developed flows between i nfinite parallel planes. The present turbulence model is a modified version of the Launder & Sharma''s k-ε model (LS model), in which the gradient production term in ε-equation is modeled to have only the normal derivative terms. The present predictions for drag reduction behavior such as the maximum drag reduction and effects of riblets on turbulence quantities are in good agreement with both the experiments and the recent DNS results: differences in the mean velocity profile and turbulent quantities are found to be limited to the riblet cavity region. Turbulence quantities are also reduced in drag-reducing configurations. Possible shortcomings in the present model using an isotropic turbulent viscosity are also discussed particularly with reference to the absence of any turbulence-driven Secondary motions.