A drag estimation method of single tetrahedral frame in multi-direction flow

Revetments of tetrahedral frame are being used more and more in river engineering in China. Due to their complex geometry, it is difficult to measure the velocity fields inside them in traditional measurement methods. This limits understanding of their mechanics, potentially leads to suboptimal solutions. 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 tetrahedral frame in different flow directions environment. The realizable k-ε model is adopted for turbulent closure of the Reynolds Averaged Navier Stokes (RANS) equations. Eleven typical freestream directions which represent the typical flow environment are selected. In spite of the incidence angles of free stream are quite different, the total drags F_D do not have obvious variation, so the drags of tetrahedral frame may be regarded as “isotropic” in practical applications.