The development of a stratified flow following over a sphere inside the viscous fluid in the presence of internal or surface waves

摘要

This study has used the Large Eddy Simulation (LES) for numerical simulation of internal or surface waves. The viscous stratified flow over a sphere was investigated at the Reynolds and the Froude numbers Re=2?105, Fr=1.3 for simulation of the flow over the sphere in the presence of internal waves, and at the internal Froude number Fri=25 for that in the presence of surface waves. The presence of background internal waves was found to result in an increase in the turbulent viscosity in the flow behind the sphere and in the vertical shift of the turbulent viscosity's maximum value. Moreover, their presence in the linearly stratified flow leads to a change in the density distribution of the near-surface layers of liquid. In this case the internal-wave breaking and wave mixing occur. The last one is caused by the interaction between the internal waves generated by the surface waves and the sphere.