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-   -   Dynamic Mesh- Parallel UDF (http://www.cfd-online.com/Forums/fluent-udf/71711-dynamic-mesh-parallel-udf.html)

DE HEART January 12, 2010 15:50

Dynamic Mesh- Parallel UDF
 
HI,
I am currently working on 3D FSI mechanical heart valve simulation.
the motion of the valve leaflets is assigned using a udf function.
However, i would like to run my simulation in parallel. and in order
to that i partitioned my domain in a serial mode and saved the case
and data files. then i went to parallel mode and compiled,
successfully, my udf file. However, when i try to run the simulation
in serial mode, every thing goes smooth. While when i try to switch to
the parallel one and during the first iterations a negative volume
massage show up.

For explain more about my current mesh and geometry, i uploaded the
middle plane image :
http://img684.imageshack.us/img684/4...ddileplane.png

The UDF code:

#include "udf.h"
#define omega1 -26.7 /* rotational speed-upperleaflet, rad/sec */
#define omega2 26.7 /* rotational speed-lowerleaflet, rad/sec */

DEFINE_CG_MOTION(upperleaflet, dt, cg_vel, cg_omega, time, dtime)
{
if (time >= 0.172 && time < 0.21)
{
cg_vel[0] = 0.0;
cg_vel[1] = 0.0;
cg_vel[2] = 0.0;
cg_omega[0] = omega1;
cg_omega[1] = 0.0;
cg_omega[2] = 0.0;
}

else if (time >= 0.81 && time < 0.848)
{
cg_vel[0] = 0.0;
cg_vel[1] = 0.0;
cg_vel[2] = 0.0;
cg_omega[0] = -omega1;
cg_omega[1] = 0.0;
cg_omega[2] = 0.0;
}
else {

cg_vel[0] = 0.0;
cg_vel[1] = 0.0;
cg_vel[2] = 0.0;
cg_omega[0] = 0;
cg_omega[1] = 0.0;
cg_omega[2] = 0.0;
}
return;

}

DEFINE_CG_MOTION(lowerleaflet, dt, cg_vel, cg_omega, time, dtime)
{
if (time >= 0.192 && time < 0.21)
{
cg_vel[0] = 0.0;
cg_vel[1] = 0.0;
cg_vel[2] = 0.0;
cg_omega[0] = omega2;
cg_omega[1] = 0.0;
cg_omega[2] = 0.0;
}
else if (time >= 0.81 && time < 0.828)
{
cg_vel[0] = 0.0;
cg_vel[1] = 0.0;
cg_vel[2] = 0.0;
cg_omega[0] = -omega2;
cg_omega[1] = 0.0;
cg_omega[2] = 0.0;
}
else
{
cg_vel[0] = 0.0;
cg_vel[1] = 0.0;
cg_vel[2] = 0.0;
cg_omega[0] = 0.0;
cg_omega[1] = 0.0;
cg_omega[2] = 0.0;
}
return;
}

thinktank January 12, 2010 20:17

If you go through the UDF for dynamic meshing in the tutorial in the help documentation which comes along with FLuent, you will find that you have to use commands such as !RP_HOST !RP_NODE to prevent fluent from computing certain quantities on the host, when using parallel computing..

It is possible that the error you are getting is due to that, since I didnt see any such declaration in your UDF

DarrenC April 11, 2010 05:45

Hi DE_HEART

I am encountering the same problem as well. My problem is a pitching airfoil problem and I use the same DEFINE_CG_MOTION udf as you do. The problem I highly suspect is a udf problem and not a mesh partition problem because I ran a steady state solution without the udf and it runs fine and give me a solution. Only when I turn my dynamic mesh on and use libudf that i get problems after a few iterations. Have you managed to find a solution to your problem?

Regards,
Darren

almostafa67 August 5, 2010 09:54

update-dynamic-mesh failed. negative cell volume detected.
 
hi dear all...
i have this problem as you;i changed time step from 0.0001 to 0.00001 but again this message showed up,could u help me out plz?
thank u in advance for any help provided:)

Robot August 5, 2010 10:25

Dear Sir,

I'm having problem selecting few types of catalysts such as platinum-titanium oxide , platinum-silicon oxide and platinum-aluminium oxide as it is not available in the table . I had selected boundary conditions, then I selected "substrate" for zone name. When I click edit, there is no 3 types of catalysts listed in table. I also click the "porous zone" & "laminar zone" .I might not able to select any these 3 types of catalysts. Please guide me . Thanks you.

almostafa67 August 5, 2010 10:51

dear robot
if those material flow in sth like a pipe and they r working fluid u can define it in the define...> material,u can define density,viscosity,etc
hope this helps u:)

Robot August 5, 2010 21:20

Dear Sir,

My model is square shape, 2D , simple model .The pink colour represent the reaction between reactant(e.g.glycerol with steam) , with the product (e.g. as hydrogen , carbon monoxide & carbon dioxide). I had key in the reactants & the products already by selecting:

->define
->materials
:name the each reactants & products
-Selecting material type : mixture
-Fluent mixture material : mixture-template
-key in all the reactants & products in properties (mixture species : name)
-key in number of mole for each reactant & product in properties(reaction:finite rate)

All the reactants & products can be obtain from the fluent database.

The red one represent the catalyst. I need to create the catalysts (e.g platinum-titanium oxide , platinum-silicon oxide and platinum-aluminium oxide ) . How should I do it?

CAn I directly change the mesh size in the gambit file ,than convert to mesh file ,to be open in fluent software??

Robot August 5, 2010 22:07

Dear Sir,

My model is square shape, 2D , simple model .The pink colour represent the reaction between reactant(e.g.glycerol with steam) , with the product (e.g. as hydrogen , carbon monoxide & carbon dioxide). I had key in the reactants & the products already by selecting:

->define
->materials
:name the each reactants & products
-Selecting material type : mixture
-Fluent mixture material : mixture-template
-key in all the reactants & products in properties (mixture species : name)
-key in number of mole for each reactant & product in properties(reaction:finite rate)

All the reactants & products can be obtain from the fluent database.

The red one represent the catalyst. I need to create the catalysts (e.g platinum-titanium oxide , platinum-silicon oxide and platinum-aluminium oxide ) . How should I do it?

CAn I directly change the mesh size in the gambit file ,than convert to mesh file ,to be open in fluent software??

Robot August 5, 2010 22:13

Dear Sir,

Dear Sir,

My model is square shape, 2D , simple model .The pink colour represent the reaction between reactant(e.g.glycerol with steam) , with the product (e.g. as hydrogen , carbon monoxide & carbon dioxide). I had key in the reactants & the products already by selecting:

->define
->materials
:name the each reactants & products
-Selecting material type : mixture
-Fluent mixture material : mixture-template
-key in all the reactants & products in properties (mixture species : name)
-key in number of mole for each reactant & product in properties(reaction:finite rate)

All the reactants & products can be obtain from the fluent database.

The red one represent the catalyst. I need to create the catalysts (e.g platinum-titanium oxide , platinum-silicon oxide and platinum-aluminium oxide ) . How should I do it?

CAn I directly change the mesh size in the gambit file ,than convert to mesh file ,to be open in fluent software??

almostafa67 August 7, 2010 02:52

catalysts
 
dear robot...
i just found some information about catalysts in fluent tutorial docs;u can use the following function

int cat index
...sorry i'm not professional in this field and i can not help u more than this:(

Robot August 9, 2010 20:29

Dear almostafa67,

can you let me know the e-mail address so I can locate the tutorial. I hope it is not the tutorial 7 entitle " Modeling flow through porous media" as this tutorial 7 do not have the example to guide me to key in all the catalysts (e.g platinum-titanium oxide, platinium-aluminium oxide and platinum-carbon) as these three catalysts that are needed for my model , was not available in the the fluent database. I hope you can send me the website. Your guidance & help is appreciate. Thanks you. :(

Robot August 9, 2010 22:03

Dear almostafa67,

Can you let me know the website, so I can download the assignment for my 2D model that this example can guide me to key in all the catalysts (e.g platinum-titanium oxide, platinium-aluminium oxide and platinum-carbon) as these three catalysts that are needed for my model , was not available in the the fluent database. Your cooperation is much appreciate. Thanks you. :(

almostafa67 August 10, 2010 01:49

catalysts
 
dear robot...
u can download fluent 12.0 tutorial or search in internet to find ur answer,as a starting point
http://www.cfd-online.com/Forums/cd-...sing-dars.html

regards

Robot August 10, 2010 21:00

Dear almostafa67,

Should I key all the catalysts (e.g platinum-titanium oxide , platinum-aluminium oxide & platinum carbon) in the species "section" ? Hope to hear from you soon . Thanks you very much . I already download the Fluent Tutorial 12 already . hope to hera from you soon. thanks you. :(

almostafa67 August 11, 2010 01:29

robot
 
dear robot i sent u a private message yesterday:i'm new in this field and do not know how to enter catalyst's info in fluent;i wish i could help u :(
sorry


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