Effects of cross-axial perturbations on 3D Kelvin Helmholtz instability growth*

Kelvin Helmholtz instability is a phenomenon seen in nature, most notably in ocean waves and cloud formations. The simulation of Kelvin Helmholtz instability has been studied extensively in the 2D plane as well as in axisymmetric flows, analyzing the effects of various fluid conditions and initial conditions. However, as the study of Kelvin Helmholtz instability is expanded to 3D, there are additional variations in the cross-wise direction that affect the instability growth rate. The introduction of cross-axial perturbations in the initial interface initiates additional dynamics in the third direction, which results in complex 3D vorticity profiles and alters the instability amplification at the interface. The purpose of this research is to use direct numerical simulation to reveal the 3-dimensional effects of various initial conditions in Kelvin Helmholtz flow. The main focus of this study is to compare these 2D and 3D simulations to establish how significant the changes in instability growth are with the addition of multidimensional perturbations.