Week 5 - Rayleigh Taylor Instability

Rayleigh Taylor Instability

Rayleigh-Taylor (RT) instability takes place when a lighter fluid supports a heavy fluid, then any perturbation of the interface grows and leads to spikes of the heavier fluid penetrating into the lighter one and the interface becomes unstable.

Ansys setup:

Geometry setup:

create the geotry the with required parameters

Meshing :

Mesh the file with required element size

Fluent setup:

Fill the all atributes in fluent according to problem setup

solver type : pressure-based;

Time : Transient ;

Material : air and water;

solution method : coupled algaritham ;

and run the simulations

https://drive.google.com/file/d/1Xuhw7laO7iWOdbT6eQA7ZVtAYGCPgRVz/view?usp=share_link

Refained mesh

Obsevations:

When applying the grid size finer the contours come smoother and at every node we get the solutions that we required

https://drive.google.com/file/d/1VT-XikoqHdu8fUF4DR4l5SrIzeMxZFId/view?usp=share_link

The Atwood number is a dimensionless number in fluid dynamics used in the study of hydro dynamics in density stratified flows. It is a dimensionless density ratio defined as

where

= density of heavier fluid

= density of lighter fluid