Problem in using buoyantBoussinesqSimpleFoam for Thermal Stacking simulation

bhargav1195 · January 22, 2018, 09:47

Hello Everyone,

Background

I am trying to simulate the high rise building model to analyse the thermal stacking effect due to ODU(Out-Door Unit). I am using buoyantBoussinesqSimpleFoam solver. At First, I have created model for single floor and want to extend that further for 33 floors if results come appropriate. I have used Salome for generating the Tet-Mesh of the floor.

Problem

While running the buoyantBoussinesqSimpleFoam solver, the values of Bounding k and Bounding epsilon goes as high as in the range of e+47 after 5 iterations and then solver stops with error. I have calculated values of k and epsilon according to empirical formulae available but I don't have idea how to overcome this error.

Can anyone help me out with this problem please?

Thank You

Regards,
Bhargav

PanPeter · January 22, 2018, 21:10

Hi Bhargav,

Have you tried running your case without turbulence modeling? Is your simulation crashing in that case too?

It would help if you posted a small example case that reproduces the error.

cheers
Fynn

bhargav1195 · January 22, 2018, 23:38

Hi Fynn,

No I have not tried the case without turbulence modelling because I am trying to simulate the case for validation of the same case using different CFD Package, Hence If I will not use the same condition than results will vary. Anyhow, just to check the working of solver I will run the case without the Turbulence model and update here.

Meanwhile, I am sharing the 0 and System sub-directory folder link here. Can you please check it to give possible remedy if possible?

https://drive.google.com/open?id=1Iy...1zGsuzkh0l5_Eq

Thank You

Regards,
Bhargav

PanPeter · January 24, 2018, 22:40

Hi Bhargav,

I looked at your files and they seem fine. But it's hard to say where the error might be with only this little information you're providing.

You would make it easier for people to understand your problem if you posted the error message, together with a minimal example reproducing the error and stated the things your tried to solve your problem.

As to the turbulence: Although you want to compare case including turbulence, I'd switch it off for now to see if this is the source of error. The divergence of the k and epsilon fields might point to a problem in the turbulent modelling but remember that these fields are calculated from the velocity field, so turbulence modeling is probably not your problem.

cheers
Fynn

bhargav1195 · January 29, 2018, 02:27

Hello Fynn,

Thank you so much for helping me with this problem.

I have uploaded picture explaining my model and showing imp boundary conditions. While running the buoyantBoussinesqSimpleFoam, the error I am getting that too I have uploaded in the log file.

Kindly find the link of my uploads here:
https://drive.google.com/open?id=1Iy...1zGsuzkh0l5_Eq

Problem definition of Analysis: Study the temperature and Pressure variation around the building due to Out-Door Unit present at each floor. I have specified inlet and outlet boundaries for airflow from/outof ODU.

I want to do the analysis for 33 floor but first I am testing it with Floor 1. Only temperature and pressure values are important for the analysis. Hence, by having a look at Model, Files and error message can you suggest me where to improve?

regarding your suggestion for running the case first without turbulence model, as per my understanding I have to run the case using PotentialFoam. I have tried that too by using only P and U files,but in that also i am getting error that too I have uploaded.

Your kind help and time is much appreciated. Thank You so much.

Regards,
Bhargav

PanPeter · February 11, 2018, 22:59

Hi Bhargav,
sorry for the late reply. You didn't supply a log file with the error message. Just post it here.

From you sketch it looks like your building height direction is along the Z-direction. But you defined gravity to act in the -Y-direction. You probably don't want that.

cheers
Fynn

bhargav1195 · February 11, 2018, 23:52

Hello Fynn,

Thank you so much for your help. That issue has been resolved. In the p_rgh file I was giving wrong input which lead to the divergence. Now I have been able to run the simulation for one floor and I will further trouble you if I come across any roadblock.

Thank you so much for your time and efforts.

Regards,
Bhargav

January 22, 2018, 09:47	Problem in using buoyantBoussinesqSimpleFoam for Thermal Stacking simulation	#1
bhargav1195 New Member Bhargav lakhlani Join Date: Jan 2018 Posts: 22 Rep Power: 8	Hello Everyone, Background I am trying to simulate the high rise building model to analyse the thermal stacking effect due to ODU(Out-Door Unit). I am using buoyantBoussinesqSimpleFoam solver. At First, I have created model for single floor and want to extend that further for 33 floors if results come appropriate. I have used Salome for generating the Tet-Mesh of the floor. Problem While running the buoyantBoussinesqSimpleFoam solver, the values of Bounding k and Bounding epsilon goes as high as in the range of e+47 after 5 iterations and then solver stops with error. I have calculated values of k and epsilon according to empirical formulae available but I don't have idea how to overcome this error. Can anyone help me out with this problem please? Thank You Regards, Bhargav

January 22, 2018, 21:10		#2
PanPeter Member Fynn Join Date: Feb 2016 Posts: 48 Rep Power: 10	Hi Bhargav, Have you tried running your case without turbulence modeling? Is your simulation crashing in that case too? It would help if you posted a small example case that reproduces the error. cheers Fynn bhargav1195 likes this.

January 22, 2018, 23:38	Case_Files	#3
bhargav1195 New Member Bhargav lakhlani Join Date: Jan 2018 Posts: 22 Rep Power: 8	Hi Fynn, No I have not tried the case without turbulence modelling because I am trying to simulate the case for validation of the same case using different CFD Package, Hence If I will not use the same condition than results will vary. Anyhow, just to check the working of solver I will run the case without the Turbulence model and update here. Meanwhile, I am sharing the 0 and System sub-directory folder link here. Can you please check it to give possible remedy if possible? https://drive.google.com/open?id=1Iy...1zGsuzkh0l5_Eq Thank You Regards, Bhargav

January 24, 2018, 22:40		#4
PanPeter Member Fynn Join Date: Feb 2016 Posts: 48 Rep Power: 10	Hi Bhargav, I looked at your files and they seem fine. But it's hard to say where the error might be with only this little information you're providing. You would make it easier for people to understand your problem if you posted the error message, together with a minimal example reproducing the error and stated the things your tried to solve your problem. As to the turbulence: Although you want to compare case including turbulence, I'd switch it off for now to see if this is the source of error. The divergence of the k and epsilon fields might point to a problem in the turbulent modelling but remember that these fields are calculated from the velocity field, so turbulence modeling is probably not your problem. cheers Fynn bhargav1195 likes this.

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January 29, 2018, 02:27		#5
bhargav1195 New Member Bhargav lakhlani Join Date: Jan 2018 Posts: 22 Rep Power: 8	Hello Fynn, Thank you so much for helping me with this problem. I have uploaded picture explaining my model and showing imp boundary conditions. While running the buoyantBoussinesqSimpleFoam, the error I am getting that too I have uploaded in the log file. Kindly find the link of my uploads here: https://drive.google.com/open?id=1Iy...1zGsuzkh0l5_Eq Problem definition of Analysis: Study the temperature and Pressure variation around the building due to Out-Door Unit present at each floor. I have specified inlet and outlet boundaries for airflow from/outof ODU. I want to do the analysis for 33 floor but first I am testing it with Floor 1. Only temperature and pressure values are important for the analysis. Hence, by having a look at Model, Files and error message can you suggest me where to improve? regarding your suggestion for running the case first without turbulence model, as per my understanding I have to run the case using PotentialFoam. I have tried that too by using only P and U files,but in that also i am getting error that too I have uploaded. Your kind help and time is much appreciated. Thank You so much. Regards, Bhargav

February 11, 2018, 22:59		#6
PanPeter Member Fynn Join Date: Feb 2016 Posts: 48 Rep Power: 10	Hi Bhargav, sorry for the late reply. You didn't supply a log file with the error message. Just post it here. From you sketch it looks like your building height direction is along the Z-direction. But you defined gravity to act in the -Y-direction. You probably don't want that. cheers Fynn

February 11, 2018, 23:52		#7
bhargav1195 New Member Bhargav lakhlani Join Date: Jan 2018 Posts: 22 Rep Power: 8	Hello Fynn, Thank you so much for your help. That issue has been resolved. In the p_rgh file I was giving wrong input which lead to the divergence. Now I have been able to run the simulation for one floor and I will further trouble you if I come across any roadblock. Thank you so much for your time and efforts. Regards, Bhargav