How to introduce meshing elements at desired locations

enr_venkat · February 27, 2010, 03:40

Hi,

Could any one guide me to dense certain locations with meshing elements so as to capture the required physics for CFD simulation ? I have both solid and fluid in the computational domain. Temperature distribution on the solid has to be simulated using ANSYS CFX. I've tried element sizing with both hard/soft options and virtual topology to clean up certain sharp edges and bends. I've created different Body sizing for Fluid volume and solid domain. I've tried the option " Number of cells across the gap" . But i found this option to increase the mesh density of entire body. How can i control it at desired locations ? I'm interested in capturing boundary layers and need to conform to y+ value to be less than 1. How do i relate first layer height to y+ value so as to achieve the required ones? Does number of inflation layers really influence the Y+ value control ? I'm sorry if i was interrogative. I'm a beginner in CFD Meshing using independent meshign tool like ANSYS MESHING. Please advise as early as possible. Many thanks

jsm · February 28, 2010, 23:53

Hi Venkat,

In Ansys meshing, right click on the mesh icon and you can find "insert --> Inflation". By using this, you can create boundary layers near walls.

Hope this will help U

enr_venkat · March 1, 2010, 23:55

Thanks for your info. I'm aware of the inflation option that creates boundary layers. We have three methods of inflation such as smoothing, first layer thickness and total thickness. Using any of these options, is there any thumb rule to match the inflation layer height equivalent to Y+ (<1). I would like to know about mesh local refinement. How do we do it ? Apart from the option, "Number of cells across the gap", is there any other feature that helps in local refinement ?

George Chen 28 · March 8, 2010, 21:07

first of all, I don't know any about Ansy meshing. But, I remeber that fluent has "adapt" function. it means Fluent can refine or coarsen meshing by the method you choiced when iteration is going. I think it meets your requirement. Am I right? hope it can help.

enr_venkat · March 8, 2010, 23:54

The problem is that i use only ANSYS CFX. If you know any valuable options in CFX, you are most welcome for further suggestions.

George Chen 28 · March 9, 2010, 06:39

sorry, I am new to CFD. I only know a little about Gambit and Fluent. hope you could solve the problem soon.

February 27, 2010, 03:40	How to introduce meshing elements at desired locations	#1
enr_venkat Member Venkat Join Date: Nov 2009 Posts: 35 Rep Power: 17	Hi, Could any one guide me to dense certain locations with meshing elements so as to capture the required physics for CFD simulation ? I have both solid and fluid in the computational domain. Temperature distribution on the solid has to be simulated using ANSYS CFX. I've tried element sizing with both hard/soft options and virtual topology to clean up certain sharp edges and bends. I've created different Body sizing for Fluid volume and solid domain. I've tried the option " Number of cells across the gap" . But i found this option to increase the mesh density of entire body. How can i control it at desired locations ? I'm interested in capturing boundary layers and need to conform to y+ value to be less than 1. How do i relate first layer height to y+ value so as to achieve the required ones? Does number of inflation layers really influence the Y+ value control ? I'm sorry if i was interrogative. I'm a beginner in CFD Meshing using independent meshign tool like ANSYS MESHING. Please advise as early as possible. Many thanks

February 28, 2010, 23:53		#2
jsm Senior Member JSM Join Date: Mar 2009 Location: India Posts: 192 Rep Power: 20	Hi Venkat, In Ansys meshing, right click on the mesh icon and you can find "insert --> Inflation". By using this, you can create boundary layers near walls. Hope this will help U __________________ With regards, JSM

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March 1, 2010, 23:55		#3
enr_venkat Member Venkat Join Date: Nov 2009 Posts: 35 Rep Power: 17	Thanks for your info. I'm aware of the inflation option that creates boundary layers. We have three methods of inflation such as smoothing, first layer thickness and total thickness. Using any of these options, is there any thumb rule to match the inflation layer height equivalent to Y+ (<1). I would like to know about mesh local refinement. How do we do it ? Apart from the option, "Number of cells across the gap", is there any other feature that helps in local refinement ?

March 8, 2010, 21:07		#4
George Chen 28 New Member Join Date: Mar 2010 Posts: 22 Rep Power: 16	first of all, I don't know any about Ansy meshing. But, I remeber that fluent has "adapt" function. it means Fluent can refine or coarsen meshing by the method you choiced when iteration is going. I think it meets your requirement. Am I right? hope it can help.

March 8, 2010, 23:54		#5
enr_venkat Member Venkat Join Date: Nov 2009 Posts: 35 Rep Power: 17	The problem is that i use only ANSYS CFX. If you know any valuable options in CFX, you are most welcome for further suggestions.

March 9, 2010, 06:39		#6
George Chen 28 New Member Join Date: Mar 2010 Posts: 22 Rep Power: 16	sorry, I am new to CFD. I only know a little about Gambit and Fluent. hope you could solve the problem soon.