CFD analysis has stopped becuse of solver exited unexpectdely

[Anonymous]

Hi Experts, My_design in CFD getting stopped unexpectedly as shown in pic attached. Whenever I enter the number of "iterations to run" 100, It runs up-to 82 and stops and gives the error. If I enter runs up-to 50 it stopes at 32 etc. I am unable to solve because the help at the below link does not help me. I did all the trials to resolve this. http://help.autodesk.com/view/SCDSE/2015/ENU/?caas=caas/sfdcarticles/sfdcarticles/Error-Message-Anal... Can anybody help on this ? Its very urgent as I am unable to produce the any results or to see the results. Many Thanks, Chandra

[Anonymous]

Hi Experts, My_design in CFD getting stopped unexpectedly as shown in pic attached. Whenever I enter the number of "iterations to run" 100, It runs up-to 82 and stops and gives the error. If I enter runs up-to 50 it stopes at 32 etc. I am unable to solve because the help at the below link does not help me. I did all the trials to resolve this. http://help.autodesk.com/view/SCDSE/2015/ENU/?caas=caas/sfdcarticles/sfdcarticles/Error-Message-Anal... Can anybody help on this ? Its very urgent as I am unable to produce the any results or to see the results. Many Thanks, Chandra

[Jon.Wilde]

Hi Chandra,

This is most likely to be an error in the setup, are you able to share a CFZ?

Thanks,

Jon

[Jon.Wilde]

Hi Chandra,

This is most likely to be an error in the setup, are you able to share a CFZ?

Thanks,

Jon

[Anonymous]

Hi John,

Pls find the below link to see what is happaning at my side.

http://screencast.com/t/rgCi79Up8

Many Thanks,

Chandra

[Anonymous]

Hi John,

Pls find the below link to see what is happaning at my side.

http://screencast.com/t/rgCi79Up8

Many Thanks,

Chandra

[Jon.Wilde]

Looks like a poor setup to me still, at the least the mesh is too coarse. It is tough to troubleshoot this one from a video though, please share a CFZ.

[Jon.Wilde]

Looks like a poor setup to me still, at the least the mesh is too coarse. It is tough to troubleshoot this one from a video though, please share a CFZ.

[Anonymous]

Hi Jon,
 I am not getting what you meant by CFZ ? that I am ready to share.

Thanks,
Chandra

[Anonymous]

Hi Jon,
 I am not getting what you meant by CFZ ? that I am ready to share.

Thanks,
Chandra

[Anonymous]

Hi Jon,

Issue1:
I got it.. Pls find my CFZ file here . Pls download.

http://www.screencast.com/t/IH6qWkf2o

Issue 2:
Aswell I have same type of CFZ assembly below. I have another issue here. Where I want to make the Thermal simulations. By applying a 70C heat at the bottom of the Box. but could you pls let me know what are the boundary conditions I should apply ? I am unable to see any temperature changes after I simulate, But simulation goes well. I want to make rigid body touching the square_holes_hs to Box surrounding it. and pass the air flow in any one direction. Could you pls guide me ? I am finding an unusigned body created un knowilgly, under the "square_holed_hs".

[Anonymous]

Hi Jon,

Issue1:
I got it.. Pls find my CFZ file here . Pls download.

http://www.screencast.com/t/IH6qWkf2o

Issue 2:
Aswell I have same type of CFZ assembly below. I have another issue here. Where I want to make the Thermal simulations. By applying a 70C heat at the bottom of the Box. but could you pls let me know what are the boundary conditions I should apply ? I am unable to see any temperature changes after I simulate, But simulation goes well. I want to make rigid body touching the square_holes_hs to Box surrounding it. and pass the air flow in any one direction. Could you pls guide me ? I am finding an unusigned body created un knowilgly, under the "square_holed_hs".

[Anonymous]

issue 2 : cfz file :

http://www.screencast.com/t/8GcNZO34

Many Thanks,
Chandra

[Anonymous]

issue 2 : cfz file :

http://www.screencast.com/t/8GcNZO34

Many Thanks,
Chandra

[srhusain]

Hi:

The program automatically creates parts where void are detected so you have to assign a material to these, otherwise the solver will not run. You can, of course, suppress these parts (prevent tem from meshing) if you do not want the solver to use them.

Hope this helps.

[srhusain]

Hi:

The program automatically creates parts where void are detected so you have to assign a material to these, otherwise the solver will not run. You can, of course, suppress these parts (prevent tem from meshing) if you do not want the solver to use them.

Hope this helps.

[Anonymous]

Extremely sorry, issue 2 CFZ is here:

http://www.screencast.com/t/OFzy2Hk57k

[Anonymous]

Extremely sorry, issue 2 CFZ is here:

http://www.screencast.com/t/OFzy2Hk57k

[Anonymous]

Hi Srhusain,
You mean to say the unknowingly the some parts would be created, we need to suppress them and simulate ? why will they be created is my question. Is that Body contacts we need to define ? is that lack of that ? I am unable to make that 2 body contacts rigid, if I am trying to do, the 2 center points of that bodies getting connected and becoming rigid. But I want at specific place they both should become rigid and contacted. how to do that ?


Thanks,
Chandra

[Anonymous]

Hi Srhusain,
You mean to say the unknowingly the some parts would be created, we need to suppress them and simulate ? why will they be created is my question. Is that Body contacts we need to define ? is that lack of that ? I am unable to make that 2 body contacts rigid, if I am trying to do, the 2 center points of that bodies getting connected and becoming rigid. But I want at specific place they both should become rigid and contacted. how to do that ?


Thanks,
Chandra

[Jon.Wilde]

Hi,

I am not 100% sure on the goal here yet.

Model 1

I think perhaps you need to draw an air block (in CAD) around the upper portion of this model and apply a flow rate and temp at the inlet and a P=0 at the outlet

You cannot apply flow rates to a solid.

We also must ensure all boundary conditions (BC's) are external - so leave the bottom of the unit outside of the air so you can apply a temperature.

I would not recommend changing the solver settings from the default initially not sure why this is set to laminar?

Model 2

This makes more sense - but just draw a solid  block in CAD (in most packages it can overlap the part) and then just call it 'air' in CFD. Apply BC's to this.

Or you can use the Geometry Tools in CFD to fill the solid you have (void-fill) and then be sure to suppress the outer solid part from the mesh to avoid internal BC's. The part you create will be air.

Have you run through any of our tutorial models? This should really help make it clear.

Thanks,

Jon 

[Jon.Wilde]

Hi,

I am not 100% sure on the goal here yet.

Model 1

I think perhaps you need to draw an air block (in CAD) around the upper portion of this model and apply a flow rate and temp at the inlet and a P=0 at the outlet

You cannot apply flow rates to a solid.

We also must ensure all boundary conditions (BC's) are external - so leave the bottom of the unit outside of the air so you can apply a temperature.

I would not recommend changing the solver settings from the default initially not sure why this is set to laminar?

Model 2

This makes more sense - but just draw a solid  block in CAD (in most packages it can overlap the part) and then just call it 'air' in CFD. Apply BC's to this.

Or you can use the Geometry Tools in CFD to fill the solid you have (void-fill) and then be sure to suppress the outer solid part from the mesh to avoid internal BC's. The part you create will be air.

Have you run through any of our tutorial models? This should really help make it clear.

Thanks,

Jon 

[srhusain]

Hi: This feature is more a convenience in that frequently the original CAD model usually represents the solid parts and SimCFD detects enclosures/voids and creates additional parts- it does not modify the original geometry in the CAD files. This saves the user considerable time by avoiding the need to explicitly create the fluid domain in the CAD environment.

If you do not want the mesher to mesh these you can simply suppress them, but you still have to assign these filled voids a material- any material will suffice.

[srhusain]

Hi: This feature is more a convenience in that frequently the original CAD model usually represents the solid parts and SimCFD detects enclosures/voids and creates additional parts- it does not modify the original geometry in the CAD files. This saves the user considerable time by avoiding the need to explicitly create the fluid domain in the CAD environment.

If you do not want the mesher to mesh these you can simply suppress them, but you still have to assign these filled voids a material- any material will suffice.

[Anonymous]

srhusain,

Many Thanks sir. It clarifies me, what I should enter the materials. How to suppress the newly created objects.
Chandra

[Anonymous]

srhusain,

Many Thanks sir. It clarifies me, what I should enter the materials. How to suppress the newly created objects.
Chandra

[Anonymous]

Hi Jon,
I have discontinued the Model 1, because Model 2 make sense, as you guided.
The goal is : Study the heat sink fin here, and produce the results to draw the graph for the below
1. Reynolds numbers (50 to 500) verses Heat Flux
2. Renolds number verses Max base temperature of the heat sink.

But still, the issue of the Auto stop is happening for me.
Pls get my CFZ file as below. Pls see my issue in a vedio.

CFZ file: http://www.screencast.com/t/tWaODWN6sr46
Issue Vedio: http://screencast.com/t/9HO5q1Pf


I more question is for the Reynolds numbers (50, 100,till 500 etc). Could you correct me ? Because I entered "volume flow rate" as : 0.0036 = 51 (as my Reynolds number). Is this correct as per below online link :
http://airfoiltools.com/calculator/reynoldsnumber?MReNumForm%5Bvel%5D=0.0036&MReNumForm%5Bchord%5D=0...

Many Thanks Jon,
Your help is too much precious to me, after discussing with you, now I could make it little progress to produce the results. Still expecting your further help in completely getting successful results as I wanted.

Best Regards,
Chandra

[Anonymous]

Hi Jon,
I have discontinued the Model 1, because Model 2 make sense, as you guided.
The goal is : Study the heat sink fin here, and produce the results to draw the graph for the below
1. Reynolds numbers (50 to 500) verses Heat Flux
2. Renolds number verses Max base temperature of the heat sink.

But still, the issue of the Auto stop is happening for me.
Pls get my CFZ file as below. Pls see my issue in a vedio.

CFZ file: http://www.screencast.com/t/tWaODWN6sr46
Issue Vedio: http://screencast.com/t/9HO5q1Pf


I more question is for the Reynolds numbers (50, 100,till 500 etc). Could you correct me ? Because I entered "volume flow rate" as : 0.0036 = 51 (as my Reynolds number). Is this correct as per below online link :
http://airfoiltools.com/calculator/reynoldsnumber?MReNumForm%5Bvel%5D=0.0036&MReNumForm%5Bchord%5D=0...

Many Thanks Jon,
Your help is too much precious to me, after discussing with you, now I could make it little progress to produce the results. Still expecting your further help in completely getting successful results as I wanted.

Best Regards,
Chandra

[Anonymous]

Hi Jon,
Because of the not successfully completed the simulation. I am guessing that , the results are available only with "parts", "wall calculator" is possible. the actual results analysis like "Global", "planes", "Iso surfaces" are getting generated for me. Could you pls help me ?

Thanks
Chandra

[Anonymous]

Hi Jon,
Because of the not successfully completed the simulation. I am guessing that , the results are available only with "parts", "wall calculator" is possible. the actual results analysis like "Global", "planes", "Iso surfaces" are getting generated for me. Could you pls help me ?

Thanks
Chandra

[Jon.Wilde]

Hi,

I can make a few comments:

1. You still have no air volume and are applying conditions to the solid (which should be suppressed from the mesh and 100% ignored)
2. Why not just draw the air volume (the wind tunnel) in CAD? It would just be a very simple solid block, not a tube. The 
3. The conditions on it will be Inlet: Flow Rate and Temp. Outlet: P=0
4. You still have internal boundary conditions - the temp and heat flux underneath the part. Ensure that when you draw the large air block, this surface is on te edge of the model, not internal. I would have thought you need only a temp or a heat flux and not both
5. I am unsure what the small air block underneat the part is, delete this too I think
6. Check out our car tutorial model. )It has no car included, just a void where you would have a solid part) but it should help you understand that we need a large cuboid of air and nothing more, pretty simple 🙂

I hope that helps,

Thanks,

Jon

[Jon.Wilde]

Hi,

I can make a few comments:

1. You still have no air volume and are applying conditions to the solid (which should be suppressed from the mesh and 100% ignored)
2. Why not just draw the air volume (the wind tunnel) in CAD? It would just be a very simple solid block, not a tube. The 
3. The conditions on it will be Inlet: Flow Rate and Temp. Outlet: P=0
4. You still have internal boundary conditions - the temp and heat flux underneath the part. Ensure that when you draw the large air block, this surface is on te edge of the model, not internal. I would have thought you need only a temp or a heat flux and not both
5. I am unsure what the small air block underneat the part is, delete this too I think
6. Check out our car tutorial model. )It has no car included, just a void where you would have a solid part) but it should help you understand that we need a large cuboid of air and nothing more, pretty simple 🙂

I hope that helps,

Thanks,

Jon

[Anonymous]

Hi Jon,

I have done as you suggested. Making whole external block as Air and solving. Here I have few questions.

1. I assigned the 4500W/m^2 as heat flux constant to the base of the Square holed Heat sink , inside the air block. My experiment is to heat the base of square holed Heat sink with a heat of 70 Celsius, and blow the air and then measure the base and fin of the square holed heat sink temperatures. So I selected "volume" applied "Total heat generation" as 70 Celsius. Is this correct ?

2. after simulation The square holed heat sink not showing me the any Heat maps, it should be little red hot.. no sign of it!! what would be happening ?

3. I also want to calculate the part wise heat recorded. The units are showing me in Farenheat. any help in seeing the units in Celsius ? Even though I make the pop uped windows with Celsius, when I push button. It shows me in Farenheat. any help ?

Pls find my CFZ file to understand the issues .

http://www.screencast.com/t/f7lSSkJBBi

Many Thanks for your help. I am almost done , need little more your inputs.
Chandra

[Anonymous]

Hi Jon,

I have done as you suggested. Making whole external block as Air and solving. Here I have few questions.

1. I assigned the 4500W/m^2 as heat flux constant to the base of the Square holed Heat sink , inside the air block. My experiment is to heat the base of square holed Heat sink with a heat of 70 Celsius, and blow the air and then measure the base and fin of the square holed heat sink temperatures. So I selected "volume" applied "Total heat generation" as 70 Celsius. Is this correct ?

2. after simulation The square holed heat sink not showing me the any Heat maps, it should be little red hot.. no sign of it!! what would be happening ?

3. I also want to calculate the part wise heat recorded. The units are showing me in Farenheat. any help in seeing the units in Celsius ? Even though I make the pop uped windows with Celsius, when I push button. It shows me in Farenheat. any help ?

Pls find my CFZ file to understand the issues .

http://www.screencast.com/t/f7lSSkJBBi

Many Thanks for your help. I am almost done , need little more your inputs.
Chandra

[Jon.Wilde]

Hi,

I can only see a cfdst, please send the CFZ and I'll take a peek 🙂

Mind you, I'm not so hot on using screencast to share files, maybe I'm just not seeing it.

1. Just be sure you are not assigning any internal surface boundary conditions. The exception is a heat generation to a volume. I am not sure how you assigned a 70C heat generation, I would have thought you assigned 70W? If so, yes that is OK
2. Not sure yet 🙂 Do you have a temp and flow rate on the main air inlet?
3. This is dependent on the units you ran the analysis in, check this in the top left (Geometry). You can only change them before you run so would need to start from a fresh CFZ if you want to change

Kind regards,

Jon

[Jon.Wilde]

Hi,

I can only see a cfdst, please send the CFZ and I'll take a peek 🙂

Mind you, I'm not so hot on using screencast to share files, maybe I'm just not seeing it.

1. Just be sure you are not assigning any internal surface boundary conditions. The exception is a heat generation to a volume. I am not sure how you assigned a 70C heat generation, I would have thought you assigned 70W? If so, yes that is OK
2. Not sure yet 🙂 Do you have a temp and flow rate on the main air inlet?
3. This is dependent on the units you ran the analysis in, check this in the top left (Geometry). You can only change them before you run so would need to start from a fresh CFZ if you want to change

Kind regards,

Jon

[Anonymous]

Hi Jon,

Thanks for the email. I am sorry , I was doing "uick reply", hence was unable to attcahfile here itself, insted using third part website.

Its OK.  Pls have alook with CFZ file, I have put below Boundary conditions:

1. Inlet of air block:

   Pressure= 0 psi,

  Temparature 22C;

  Volume Flow rate: 50 m3/s

2.outlet of the air block:

pressoue =0 psi

3. Bottom of the Square holed heat sink base:

 Heat Flux = 4500 w/m2

 Heat genaration = 70 Watts( sorry last time I used wrong units here)

Could you pls guide me now.

 Thanks agaian,

 Chandra

[Anonymous]

Hi Jon,

Thanks for the email. I am sorry , I was doing "uick reply", hence was unable to attcahfile here itself, insted using third part website.

Its OK.  Pls have alook with CFZ file, I have put below Boundary conditions:

1. Inlet of air block:

   Pressure= 0 psi,

  Temparature 22C;

  Volume Flow rate: 50 m3/s

2.outlet of the air block:

pressoue =0 psi

3. Bottom of the Square holed heat sink base:

 Heat Flux = 4500 w/m2

 Heat genaration = 70 Watts( sorry last time I used wrong units here)

Could you pls guide me now.

 Thanks agaian,

 Chandra

[Jon.Wilde]

Hi,

Your conditions need to be:

Inlet

v = 50m3/s (is that really correct? It seems awfully fast!). Maybe you mean m/s?

T = 22C

(We cannot have both vel and pressure at the inlet as the model would be over constrained)

Outlet

P=0

Draw the air box in CAD so the bottom aligns with the unit - so you can have the heat flux outside and not inside the air domain. We must not have internal surface boundary conditions.

Right now you have a really small gap. Whatever you choose next, do make this change, a small gap like this will cause meshing issues.

Do you really need the 70W volumetric load, the 70C temp underneath and the 4500 W/m2 heat flux? I think the temp needs to be deleted. Always check through the setup.

Once you have made those changes - you will need to refine the mesh as the default is going to be too coarse for accurate results. I would start with a refinement to 0.3 and go from there.

Should look something like this. I used 50m/s and was not able to change the CAD as you need to (so I had no heat flux either).

Kind regards,

Jon

[Jon.Wilde]

Hi,

Your conditions need to be:

Inlet

v = 50m3/s (is that really correct? It seems awfully fast!). Maybe you mean m/s?

T = 22C

(We cannot have both vel and pressure at the inlet as the model would be over constrained)

Outlet

P=0

Draw the air box in CAD so the bottom aligns with the unit - so you can have the heat flux outside and not inside the air domain. We must not have internal surface boundary conditions.

Right now you have a really small gap. Whatever you choose next, do make this change, a small gap like this will cause meshing issues.

Do you really need the 70W volumetric load, the 70C temp underneath and the 4500 W/m2 heat flux? I think the temp needs to be deleted. Always check through the setup.

Once you have made those changes - you will need to refine the mesh as the default is going to be too coarse for accurate results. I would start with a refinement to 0.3 and go from there.

Should look something like this. I used 50m/s and was not able to change the CAD as you need to (so I had no heat flux either).

Kind regards,

Jon