Numerical study on mean and turbulent characteristics of an oscillating jet under the effect of currents

Abstract

The mean flow and turbulent characteristics of oscillating jets in the current environment are investigated using a three-dimensional large eddy simulation (LES) model. The effect of dimensionless parameters on oscillating jets is analyzed. Moreover, the mean flow velocity distributions of the downstream sections in the oscillating jet in the current environment and wave-current coexisting environment are compared. The results show that increasing the jet-to-current velocity ratio (R_jc) and the amplitude-to-jet velocity ratio (R_aj) can significantly increase the impact height and spreading range of the jet column, reduce its bending degree, and increase turbulence intensity, whereas the Strouhal number (S_t) has a minimal effect on the motion of the oscillating jet. Oscillating jets in a current environment and non-oscillating jets in a wave-current coexisting environment exhibit similar flow characteristics and mean velocity distributions, particularly when R_aj/R_wc is small, but the inconsistency in the range of action leads to stronger vertical penetration of the oscillating jets. This study reveals that the oscillating jet has a positive effect on mixing and dilution.