CFD Online Discussion Forums

CFD Online Discussion Forums (
-   CFX (
-   -   Moving of the mesh (

Diego Augusto February 16, 2007 10:08

Moving of the mesh
Hi I am working with a border problem movel, in the reality is about the one simulation chamber of combustion where I am trying to make the piston if to put into motion a function in accordance with sinoidal, I obtain to inside get movement of mesh of the cylinder however the border movel (piston) don't if puts into motion. What it must make? Debtor!

Glenn Horrocks February 18, 2007 17:48

Re: Moving of the mesh

CFX can model piston/cylinder assemblies. Make the cylinder top a stationary wall, the piston a moving wall with the prescribed motion and the cylinder side walls a wall with unspecified motion.

An important trick to get it to work is to generate the mesh at top dead centre and stretch the mesh out to BDC rather than the other way around. If you squash a BDC mesh to TDC the internal mesh smoothing algorithm has problems with large compression ratioes (eg 10:1) and generates negative volume elements. The mesh smoothing algorithm works well as the mesh is stretched.

Glenn Horrocks

Diego Augusto March 26, 2007 16:41

Re: Moving of the mesh

I obtained to make simulations of piston of an engine in the CFX, but I obtained to reach the tax of compression that I need, what I must make so that the piston goes up more? How much to the movement of valve I obtained dislocates them very little, therefore whenever the movement of valve if initiates occurs error in the CFX, what I must make?

Diego Augusto

All times are GMT -4. The time now is 07:57.