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June 26, 2009, 16:58 
3D mesh

#41 
Member
amin
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hi Dear Niklas
what is my mistake? what is its correction? how can i describe an axisymmetric mesh for diesel foam? I ran a 3D simulation of dieselfoam with last characteristic of nheptane experiment and add its result to a new plot and attached it. there are two strange things: 1 I saw some fluctuations in liquid penetration curve in 3D cases. 2 likewise liquid penetration is far from experimental result. what is the reason of these? I set the initial drop diameter to nozzle diameter according to injector model.is it correct? I am confused. Please help me. thanks regard Last edited by az1362f; June 27, 2009 at 11:31. 

June 27, 2009, 13:35 
axisymmetric Mesh

#42 
Member
amin
Join Date: May 2009
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Hi
I tried to solve last problem that I discussed in my last posts by axisymmetric mesh but my results likewise were incorrect and far from experimental result. I attached axisymmetric Mesh. please check my axisymmetric blockmesh. is it correct? I tried to 3D simulation of dieselfoam of nheptane experiment but results were far from experiment and had fluctuations. Why are my result far from experiment? please help me. Thanks regard 

June 29, 2009, 11:29 
axisymmetric Mesh

#43 
Member
amin
Join Date: May 2009
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Hi Dr Niklas
I tried to solve last problem that I discussed in my last posts by axisymmetric mesh but my results likewise were incorrect and far from experimental result. I attached axisymmetric Mesh. please check my axisymmetric blockmesh. is it correct? I tried to 3D simulation of dieselfoam of nheptane experiment but results were far from experiment and had fluctuations. Why are my result far from experiment? please help me. Thanks regard 

June 30, 2009, 03:11 
mesh dependency

#44 
Member
amin
Join Date: May 2009
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Hi Dr Niklas;
I tried to solve axisymmetric dieselfoam for nheptane fuel,and when I compare my result by experimental result I couldn't find a mesh size of dependency. I attached my axisymmetric mesh in last posts and new plot of liquid penetration: Is my axisymmetric mesh correct? if yes why liquid penetration increased as mesh size is refined? Thanks Regard 

June 30, 2009, 04:39 

#45  
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Niklas Nordin
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Quote:
in general liquid penetration increase if you refine the mesh, thats because you resolve the jet better and hence reduce the relative velocity. You also have to investigate the influence on initial turbulent length scale, which also is very important. reducing the length scale will also increase the liquid penetration. there are no ways around these problems for lagrangian/eulerian simulations. you just have to live with the grid dependency. 

July 1, 2009, 12:45 
Validating spray

#46 
Member
amin
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Hi Dear Niklas;
then what is the way to validate spray simulation problem,when you don't know is your solution independent of mesh? regard 

July 4, 2009, 11:55 
interpolation scheme

#47 
Member
amin
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Hi Dear Niklas;
Which interpolation scheme did you use for InterPhase Coupling in dieselfoam code? Where can I see its implementation in dieselfoam code? I attached two method of InterPhase Coupling,which one did you use in dieselfoam? Thanks Regard 

July 6, 2009, 03:44 

#48 
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Niklas Nordin
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July 7, 2009, 06:22 

#49 
Member
amin
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Hi Dear NIklas;
Which of interpolation scheme did you used in dieselfoam? equation 116 or equation 117: if 117 how is it for Hexahedron cell? thanks 

July 8, 2009, 02:08 

#50 
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Niklas Nordin
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in foam its always 117.
The cell is always split into a tet containing the parcel. if you use cellPoint, it will use the nodes and cellcenter to construct the tet. if you use cellPointFace it will use the nodes, cell center and face center to construct the tet. 

July 9, 2009, 10:44 
implementation

#51 
Member
amin
Join Date: May 2009
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Hi Dear Niklas;
I am very thankful for your very good and complete answers. I have a question about where is the implementation of eq.117 in Foam? also,I studied your article by subject of "Numerical Investigation of Mesh/Turbulence/Spray Interaction for Diesel applications",you talked in this article about limiting turbulenc lengh scale, is it limited in openfoam 1.5 for dieselfoam? if no, where can i limit it? Thanks Regard Last edited by az1362f; July 11, 2009 at 17:34. Reason: adding new question 

July 11, 2009, 17:44 
turbulent length scale

#52 
Member
amin
Join Date: May 2009
Posts: 59
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Hi Dear Niklas;
I am very thankful for your very good and complete answers. I have a question about where is the implementation of eq.117 in Foam? also,I studied your article by subject of "Numerical Investigation of Mesh/Turbulence/Spray Interaction for Diesel applications",you talked in this article about limiting turbulenc length scale, is it limited in openfoam 1.5 for dieselfoam? if no, where can i limit it in the code according your article? Thanks Regard 

July 13, 2009, 11:09 
turbulence length scale

#53 
Member
amin
Join Date: May 2009
Posts: 59
Rep Power: 9 
Hi Dear Niklas;
I am very thankful for your very good and complete answers. I have a question about where is the implementation of eq.117 in Foam? also,I studied your article by subject of "Numerical Investigation of Mesh/Turbulence/Spray Interaction for Diesel applications",you talked in this article about limiting turbulence length scale, is it limited in openfoam 1.5 for dieselfoam? if no, where can i limit it in the code according your article? Thanks Regard 

July 20, 2009, 04:51 
finding parcel

#54 
Member
amin
Join Date: May 2009
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Hi to all,
any body knows how openfoam check the existence of particle in an eulerian cell? in the other word which function or class find if there is a parcel in the current cell? 

July 22, 2009, 12:51 
limiter

#55 
Member
amin
Join Date: May 2009
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Hello Dear Dr Nordin;
I saw in RASProperties file that for Kepsilon model there are two parameters for limiter :" muLimiter on;Lsgs 0.0002; are these parameters activate turbulent length scale limiter in openFoam version 1.5? please answer me. thanks regard 

September 28, 2009, 11:32 

#57 
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Christof Benz
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Hi,
i use octave/matlab to calculate penetration length. the position of the parcel you can find in $FOAM_CASE/timeDirectory/lagrangian/defaultCloude/position. The liquid is defined in $FOAM_CASE/thermophysicalProperites Christof 

October 1, 2009, 06:23 

#58  
New Member
HuangWei
Join Date: Mar 2009
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Quote:
i have found the "position" file ,but i want to know how to calculate penetration length.Thank you very much,Christof huoyinghw 

October 26, 2011, 04:12 

#59  
New Member
Join Date: Jan 2011
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Quote:
Hello Amin, how did you implement this function can you share it, i m having this problem to implement in dieselFoam 

June 12, 2012, 22:42 

#60 
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hi dude,I confront a problem similar to yours now, where should I go to for changing the chem.inp and therm.dat files?


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