Drag estimation of single tetrahedron block in multi-direction flow surroundings

Tetrahedron Block (TB) is a commonly used material in river closure and dike protection engineering. A 3D hydrodynamic model, which is based on the commercial Computational Fluid Dynamics (CFD) code Fluent, is developed to predict velocity fields and drags of the single TB in flow with different free stream directions. The realizable k-ε model is adopted for turbulent closure of the Reynolds Averaged Navier Stokes (RANS) equations. The study demonstrates that the numerical model can help in understanding the complex flow fields around the TB. When the directions of the free streams are changed, the total drags F_D correspondingly have obvious variation. When the Reynolds number is given as 17777, the drag coefficients C_D vary from 0.832 to 1.849, the drags of TB have an obvious "anisotropic" feature.