Numerical Simulation of Turbid-Density Current Using v2 – f Turbulence Model

摘要: The deposition behavior of fine sediment is an important phenomenon, and yet unclear to engineers concerned about reservoir sedimentation. An elliptic relaxation turbulence model (v2 – f model) has been used to simulate the motion of turbid density currents laden whit fine solid particles. During the last few years, the v2 – f turbulence model has become increasingly popular due to its ability to account for near-wall damping without use of damping functions. In addition, it has been proved that the v2 – f model to be superior to other RANS methods in many fluid flows where complex flow features are present. Due to low Reynolds number turbulence of turbidity current, (its critical Reynolds no. is about 1000), the κ - ε model, which was standardized for high Reynolds number and isotropic turbulence flow, cannot simulate the anisotropy and non-homogenous behavior near wall. In this study, turbidity current with uniform velocity and concentration enters the channel via a sluice gate into a lighter ambient fluid and moves forward down-slope. The model has been verified with experimental data sets. Moreover, results have been compared with the standard κ - ε turbulent model. Results show that the κ - ε model has the poor result on this current. In addition, results show that the coarse particles settle down rapidly and make the higher deposition rate. The deposition of particles and the effects of their fall velocity on concentration distribution, height of body, and entrainment coefficient are also investigated.