Learning Forum

[ahmedshafie]

I wanna know if improve surface mesh help improving volume mesh or it doesnt affect it ? nDoes High surface mesh improvement make improve volume mesh need more computational cost ?nWhat is excellent , very good ,good ,acceptable volume mesh orth quality cell ?n

[Keyur Kanade]

Please improve surface mesh before generating volume mesh. Please make sure that you have surface mesh quality below 0.75. nAlso sharp angles or small gaps can give you bad cells. So make sure you do not have sharp angles or small gaps. nI assume you are going to use Fluent. For that please make sure that you have min orthogonal quality greater than 0.1. nIf it is less than 0.1, please improve volume mesh by using different sizing or modifying geometry. nRegards,nKeyurnGuidelines for Posting on Ansys Learning ForumnHow to access ANSYS help linksnn

[ahmedshafie]

nIm asking for example surface mesh is below 0.6 and volume mesh orth quality is 0.2 if i make surface mesh skewness below 0.5 does that help in making volume mesh orth quality 0.3 or it wont affect ?.Volume mesh has to be 0.1 but whats is exelent , very good ans good ? Is 0.3 very good ? Is 0.2 good ?n

[Keyur Kanade]

For orthogonal quality n0 - worstn1 - best. nIf you have min ortho quality above 0.1 then you are good to go for run. nUsually good surface mesh gives good volume mesh. nBut sharp angles and small gaps and size jumps also affect the volume mesh quality. nRegards,nKeyurnGuidelines for Posting on Ansys Learning ForumnHow to access ANSYS help linksnn

[ahmedshafie]

Thanks for your answer . Can u give me some tips to have to improve the volume mesh ? I after i made improve volume mesh i got 0.2 but i cant reach 0.3 . I tried to change cell max length ,local size and improve surface mesh but nothing changed . Shall i make body of influence ? Im using polyhedral fluent meshingn

[Keyur Kanade]

Why do you want to reach 0.3?n0.2 is good to proceed. nYou can use Auto Node Move option. nPlease search through forum about this, you would get lot of posts. You can also check help for more details nRegards,nKeyurnGuidelines for Posting on Ansys Learning ForumnHow to access ANSYS help linksnn

[ahmedshafie]

i thought increasing volume mesh quality will make fluent converge better . Am i wrong?. Thanks i will search for auto node moven

[Rob]

Improving cell quality will help, but once it's better than about 0.1 it'll work, above 0.2 and you'll not see a huge benefit of improving quality unless the flow gradients are very high. In that case you need more cells over improved cell quality. n

[ahmedshafie]

do u mean to decrease local sizing , surface meshing ,and volume meshing element sizes to increase number of elements ? Is that will help in better convergence ?n

[Rob]

Yes. It may or may not help with convergence depending on the local flow field. Remember you trade accurary for speed as you coarsen a mesh. A finer mesh is generally more accurate up to a point: read up on mesh independency studies for more details. n

[ahmedshafie]

thanks u for answer, i know how to do mesh independent test with ANSYS MESHING NOT FLUENT MESHING by parametrizing local sizing ,numbet of elements and drag force for example and change in local sizing , but how to do parametrization in FLUENT MESHING ?n

[Keyur Kanade]

For that you will need to use journal files in Fluent Meshing. nPlease go through TUI documentation. nYou will need to list down TUI required in a journal file. nThen run that journal file in Fluent Meshing. nYou can have a look at nRegards,nKeyurnGuidelines for Posting on Ansys Learning ForumnHow to access ANSYS help linksnn

[ahmedshafie]

thanks alot for your helpn