Numerical study on the transformation of an internal solitary wave propagating across a vertical cylinder

Abstract A finite volume method based 3D Cartesian grids is developed to study the effect of cylinder diameter on the evolution of a depression internal solitary wave (ISW) with different initial wave amplitudes across a vertical cylinder. This method solves the Navier–Stokes equations using an Improved Delayed Detached Eddy Simulation turbulence model. Numerical results reveal that the significant symmetric vortex shedding on the front and rear side of the cylinder during the wave-obstacle interaction, especially at the large diameter. Moreover, the vortex shedding affects the variations of the horizontal force on different depths. Results also show transmitted wave amplitude and total net horizontal force increase with initial wave amplitude and the diameter of the cylinder, in which the former is less significant than the latter, while the converse is true for the run-up height along the cylinder. In addition, the total horizontal forces on the cylinder reverse direction from compression to tension in the upper layer and conversely it is also true in the lower layer during the propagation of a depression ISW.