general doubt on solver control

arunraj · July 28, 2011, 16:46

hii,
i m generating a complete rotor ..
i have to give two simulation but with different mesh nodes..
1.70,00000 nodes
2.80,00000 nodes
In the 70,00000 mesh node definition file ..i have given outlet mass flow rate as 3 kg and inlet pressure as 1.5 atm
but my actual boundary conditions are 3.5 kg outlet mass and inlet pressure of 1.005 atm .
i have changed these details in 80,00000 mesh node definition file... nw i m planning to give the result file of 70,00000 mesh node as initialization file for the 80,00000 mesh node file in solver control ....
is it a correct methodology to use it ?... since the boundary conditions vary between the two definition files...

ghorrocks · July 28, 2011, 19:31

Don't try a mesh sensitivity study where you change parameters between meshes. The differences between meshes will be small (if you are close to a good mesh) so the mesh signal will be lost in the change in parameters.

Also a mesh change from 7n to 8n is unlikely to be large enough to be useful. See this FAQ http://www.cfd-online.com/Wiki/Ansys..._inaccurate.3F and the link to JFE is highly recommended.

July 28, 2011, 16:46	general doubt on solver control	#1
arunraj Senior Member Arun raj.S Join Date: Jul 2011 Posts: 212 Rep Power: 16	hii, i m generating a complete rotor .. i have to give two simulation but with different mesh nodes.. 1.70,00000 nodes 2.80,00000 nodes In the 70,00000 mesh node definition file ..i have given outlet mass flow rate as 3 kg and inlet pressure as 1.5 atm but my actual boundary conditions are 3.5 kg outlet mass and inlet pressure of 1.005 atm . i have changed these details in 80,00000 mesh node definition file... nw i m planning to give the result file of 70,00000 mesh node as initialization file for the 80,00000 mesh node file in solver control .... is it a correct methodology to use it ?... since the boundary conditions vary between the two definition files...

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July 28, 2011, 19:31		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,872 Rep Power: 144	Don't try a mesh sensitivity study where you change parameters between meshes. The differences between meshes will be small (if you are close to a good mesh) so the mesh signal will be lost in the change in parameters. Also a mesh change from 7n to 8n is unlikely to be large enough to be useful. See this FAQ http://www.cfd-online.com/Wiki/Ansys..._inaccurate.3F and the link to JFE is highly recommended.