Week 5 - Rayleigh Taylor Instability

Aim: To simulate the Rayleigh Taylor Instability for two phase mixing of fluids at different densities.

Introduction: Rayleigh Taylor Instability is the interpenetration of materials that occurs whenever a light fluid pushes on a heavy fluid. It is a dynamic process whereby the two fluids seek to reduce their conbined potential energy. This instability deals with a dense, heavy fluid that is being placed above a lighter fluid in a gravity field perpendicular to interface. Examples such as water suspended above oil, mushroom clouds from volcanic eruptions, instabilities in plasma fusion reactors and inertial confinement fusion.

Theory: In this problem statement we have two fluids air and water having different densities in which water with higher densities lies over the low densities air or specific fluid separated by an interface. When this interface is disturbed then the instability situation prevails and the low density fluids get replaced by the higher density fluids and the interuptions in each and every cell is recorded for the fluid movements.

Here we have simulating the fluids of various densities as mesh independent studies and varying time steps.

Case 1: Base meshing - 0.5mm with water and air as fluidic mediums

Case 2: Base meshing - 0.1mm with water and air as fluidic mediums

Case 3: Base meshing - 0.5mm with water and specific fluid with density 400Kg/m3 and viscosity 0.001kg/ms-1

Further discussions such as Fluent Setup, meshing, solver and post processings are on notebook as per the requirements.