NUMERICAL ANALYSIS OF FLOW AROUND A SUBMERGED BODY NEAR A PYCNOCLINE USING THE GHOST FLUID METHOD ON UNSTRUCTURED GRIDS

비정렬 격자에서 Ghost Fluid 법을 이용한 밀도약층 주위 수중운동체에 의한 유동 해석

A two-layer incompressible time-accurate Euler solver is applied to analyze flow fields around a submerged body moving at a critical speed near a pycnocline. Discontinuities in the dependent variables across the material interface are captured without any dissipation or oscillation using the ghost fluid method on an unstructured grid. It is shown that the material interlace has significant effects on forces acting on a submerged body moving near a pycnocline regardless of the small difference in densities of two layers. Contrary to the shallow water waves, a submerged body can reach a critical speed at very low Froude number due to the small difference in the densities of the two layers.