Numerical Analysis of Oscillating-Grid Turbulence by Using k-ε Model

Abstract

The properties of turbulence induced by oscillating a grid vertically have been investigated by means of both numerical analysis and turbulence measurement. The turbulent field generated by an oscillating-grid is in the equilibrium between the diffusion and the dissipation of turbulent energy, and it is homogeneous in the horizontal direction. The vertical distributions of turbulent energy k, its dissipation rate ε, eddy viscosity and a characteristic length scale have been calculated by using the k-ε turbulence model. The turbulent energy and the energy flux in the vertical direction have been measured. Their vertical distri-butions agree well with the calculated results. The values of k and ε at the origin of a vertical axis of coordinates, which have been evaluated by fitting these experimental results to the calculated ones, have been related with the hydraulic conditions.