Dead nodes

[Anonymous]

When I use "Check Model" on my CFD air space, it tells me that everything is fine, but when I start the analysis it tells me that I have dead nodes and dead elements and stops the analysis. What does this mean? I can't find reference to this in help. Is there a way to identify these nodes and elements and do something about it? I have used an all tet mesh because when I try to use tets and wedges, it won't mesh at all. I have also added refinement points in relatively thin areas of the flow model to be sure there are nodes within those spaces.

[John_Holtz]

Unless you have really old software, you should be able to find the explanation by searching the help for "dead nodes" or going to the page "Autodesk Algor Simulation > Setting Up and Performing the Analysis > Setting Up Part 3 > Performing the Analysis > Performing A Fluid Flow Analysis".

[shakeel.mirza]

Hi Ralphrail,

You might be having a very abrupt variation of mesh size in the refined areas. You can solve the problem by adjusting the global size and the local refinement size to have a variation that avoids Dead elements/nodes.

If you can please share your model here or email me  at shakeel.mirza [ at ]  autodesk.com

Regards,

Shakeel

[Joey.X]

Dead nodes mean that the all nodes on an element are fully constrainted as fixed(zero velocity), and then this element is refered as dead element. Removing this element will have identical effect as the dead element invloved in the simulation, that's why it is refered as "dead". Obviously this has impact to the result accurancy.

They typically happen under using fully tetrahedral mesh, the remedy is using boundary layer mesh on the wall.

Refer to Algor's help for more explanation as John's reply before.