Numerical simulation of turbidity current using V۲-f turbulence model

The deposition behavior of fine sediment is an important phenomenon, and yet unclear to engineers concerned about reservoir sedimentation. An elliptic relaxation turbulence model ( ۲ n - f model) has been used to simulate the motion of turbid density currents laden with fine solid particles. During the last few years, the ۲ n - f turbulence model has become increasingly popular due to its ability to account for near-wall damping without use of damping functions. The ۲ n - f model has also proved to be superior to other RANS (Reynolds-Averaged Navier-Stokes) methods in many fluid flows where complex flow features are present. This current becomes turbulent at low Reynolds number (order ۱۰۰۰). The k -e model, which was standardized for high Reynolds number and isotropic turbulence flow, cannot simulate the anisotropy and nonhomogenous behavior near the wall. In this study, the turbidity current with a 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 validated by available experimental data sets. Moreover, results have been compared with the standard k -e turbulence model. The deposition of particles and the effects of their fall velocity on concentration distribution, Richardson number, and the deposition rate are also investigated. The results show that the coarse particles settle rapidly and make the deposition rate higher.

Keywords:

Density Current , Turbulence modeling , V۲ , f turbulence model