[mnazar]

can any one please clarify to me what is the difference between hard and soft behavior in sizing in meshing ? ??

[Kapi]

hard sizing is fixed sizing all across and is not changed with other neighboring edges
soft sizing is a range from minimum sizing to maximum sizing under your mesh stats. Ansys decides what sizing will go at particular location within max and min size

[Svetlana]

What Kapi said. The purpose of this is to allow ANSYS to make adjustments that contradict your values in some places but improve mesh quality.

[mnazar]

thanks for your answers..
then we can say that soft mesh usually used in dynamic mesh ?
and hard mesh used in statistical mesh?

[Svetlana]

Hard mesh can be used in dynamic mesh too. The mesh would keep changing because it is dynamic but the hard sizing controls would still be respected.

For example if turbine is moving you can use hard sizing controls on its surface and tell that there is exactly 100 mesh points along its surface. Then use a dynamic mesh and ANSYS would respect your sizing in a hard way even when generating a new mesh.

I do not know anything about statistical.

[mnazar]

okay
but not understand yet , where to use hard amd where to use soft
please give examples thanks

[Svetlana]

Usually you use soft mesh sizing everywhere and if your sizing is reasonable then ANSYS would follow it very closely. Hard mesh sizing control is an advanced option used for complex meshes which ANSYS does not want to do but the user knows that it is the best way to go for the simulation.

For example if a mesh needs to be refined in a particular region and the user knows it but ANSYS does not put effort into that region because it is not familiar with the flow.

For example an airfoil computational domain ANSYS is not very intuitive for ANSYS as it needs to have refinement behind the foil and not only next to the wall. People use hard mesh controls and mapped face sizing to force the mesh to have the structure which they need. It looks something like this, http://i58.tinypic.com/34fbjhj.jpg it is maybe not the best example but it is the only one I am familiar with at present.

[mnazar]

thankssssss it was helpful