Hi,

I'm using a 2d NS fractional step code to simulate flow past a cylinder. I'm using an o-grid. In the computational scheme, there is no special mass correction required.

Supposed after some time the cylinder will deform/morph/shrink into a smaller cylinder slowly until the radius is now half the original, do I need to do any special correction computation since the mass of cylinder is now smaller?

Btw, the shrinking cylinder is modelled using deforming grid. However, the overall computational domain size remains the same. Thank you.

You will need to ensure that geometric conservation is preserved. The original paper is an AIAA paper by Thomas and Lombard. Try googling geometric conservation.

Thanks ag. I'm aware of geometric conservation. What I am more interested in is whether there are other things which I need to consider as a result of change of mass/volume of the body.

There shouldn't be, right?

As long as you account for the grid volume changes via geometric conservation and you have accounted for the grid motion in the construction of the flux terms then you should be OK.