Investigation of internal wave wakes generated by a submerged body in a stratified flow

Abstract

Internal waves in the ocean with stratified structure are essential: natural internal waves for the untangling of physical and environmental processes in oceanography and internal waves generated by a submerged moving body for understanding the near-field flow structures and wave patterns for detection. The latter in a stratified flow with a pycnocline presented are investigated numerically in the present paper. Systematic analyses on the influences of different hydrodynamic parameters, including the Froude number (Fr), the Reynolds number (Re), the thickness of the pycnocline (ΔL), and the relative position of the submerged body (Δd), on internal wave wakes, are performed. A variation trend diagram of wake angle and wave amplitude for different parameters is obtained, showing the order of influence: Fr > ΔL > Δd > Re. For two key parameters, Fr and ΔL, scalings of wake angle variation are found. Wake angle shows a − 1 power-law dependence on Fr and the same order power law on ΔL in a critical range. In addition, vortex structures and turbulent kinetic energy distributions in the wakes are explored by comparing to the homogeneous case.