RANS 난류모델의 밀도와 부력이 규칙파 생성에 미치는 영향에 관한 연구

Abstract

When performing wave generation CFD analysis using OpenFOAM, wave damping problem occurs when the RANS turbulence model is applied with incompressible fluid. This is because RANS turbulence model in OpenFOAM assumes strictly incompressible model, not considering the effect of density, so turbulent viscosity is generated around the free surface, increasing Reynolds-stress in momentum equation. In this study, a two-dimensional regular wave generation analysis was performed and two additional turbulent models, “Density modified k-omega SST” model and “Buoyancy modified k-omega SST” model, is applied along with k-omega SST. The former one considers density on turbulence equations and the latter one adds a buoyancy term due to gravity near the free surface. As a result, when the Density modified k-omega SST and Buoyancy modified SST turbulence models were applied, the generation of the turbulent viscosity coefficient around the free surface decreased than the default k-omega SST turbulence model, improvement of wave height diffusion effect was confirmed. With the larger wave height, it was observed that the wave damping is decreased when the Buoyancy modified SST turbulence model was applied.