[nitinkumar@cfd]

Hi, Foamers, I am running a large eddy simulation of a turbulent plume in a density varying medium (stratified medium). I am comparing mean axial velocity with an experimental study. I found that qualitatively I m getting a good agreement. However quantitatively, There are differences that can be clearly seen in the velocity. I am trying to figure out why this difference or deviation is coming.

For details: I am using the dynamic k-equation model in OpenFOAM-5.0. I am using buoyantBoussinesqPimplefoam solver (which I modified for the stratified medium). Apart from that, the plume is a forced plume with initial buoyancy and momentum. I am using around 10 million cells for the computation.

I have also plotted turbulent kinetic energy (LES) with the experimental value on the centerline. I observed that resolved Kinetic energy is more as compared to experiment, which quite strange. I am not able to figure out what is the issue. I WILL BE very grateful if any experienced user help.

Also, I observed that the entrainment is less from the velocity contours.

[Tobermory]

From your second chart, it looks like the entrainment rate is higher in your LES than in the experiment, which matches the observation that the TKE levels are higher.

I know that this is an old post, but did you find a cause for the difference?