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|ID||Project||Category||View Status||Date Submitted||Last Update|
|0003025||OpenFOAM||[All Projects] Bug||public||2018-08-03 19:24||2018-08-05 12:31|
|Fixed in Version||6|
|Summary||0003025: wallHeatFlux Utility - Error in new versions - internalEnergy/Enthalpy mismatch for sonicFoam and rhoCentralFoam|
|Description||Our lab uses rhoCentralFoam and sonicFoam extensively along with the wallHeatFlux utility. We recently upgraded from 2.3 to the newest version. We have stuck with 2.3 this long as we had tested it extensively and made a few small local modifications. In doing some of our routine benchmarking, we have found that the new wallHeatFlux utility gives the wrong answer as it calls whatever form of energy is used in the solver - and perhaps the incorrect formulation of alpha. If we change the dictionary to sensibleEnthalpy, the wallHeatFlux calculation is corrected back to the answer provided by OF2.3 - which is the correct answer.|
We benchmark rhoCentralFoam against our own in-house boundary layer solver. OF 2.3 post-processing matches closely to our in-house solver prediction which is an exact numerical solution of the compressible boundary layer equations.
The difference is substantial ~30% for this test case between OF 2.3 and 5/6 postprocessing. This error is nearly constant (corresponding to roughly the % difference between Cv and Cp). Most likely, the utility should be modified to always use alpha_h and wall-normal gradient in enthalpy, or simply Fourier's law.
We have tested this rigorously, including with:
The error occurs in both 5 and 6 in any of these thermophysical configurations. Please advise if we have overlooked something simple.
Dr. W. Schuyler Hinman and Henry Stoldt (MSc. Research Student)
|Steps To Reproduce||Run post-processing in the older version (2.3) on final time step. Run post-processing again in 5 or 6. The results do not match. If you change to sensibleEnthalpy in the thermophysical properties dictionary and post-process again in 6, you recover the original (correct) answer.|
Here is a link to a google drive containing the test case:
|Additional Information||We have also found a discrepancy in the solution itself between 2.3 and 6, likely a result of a similar mismatch between alpha and gradient in energy/enthalpy. A separate bug report is to follow.|
|Tags||No tags attached.|
wallHeatFluxBug_rhoCentralFOam.ods (39,734 bytes)
||Are your tests laminar or turbulent? If turbulent with which model?|
||These are all laminar. This is to ensure the most basic benchmarking. We use a different case for testing turbulent BL.|
||I see the problem and there are a couple of ways to fix it, will work on it over the weekend.|
Thank you very much Henry. We are heavy users of OpenFOAM and greatly appreciate all your hard work. This was our first chance to try to contribute to the project.
Keep up the great work!
Please see the next bug I am about to file. It may or may not be related.
Resolved in OpenFOAM-6 by commit 1a0c91b3baa88265a11ad9dbf76c15375daf8087
Resolved in OpenFOAM-dev by commit f7100178e4c2d916da550071aa96447eefaff45c
|2018-08-03 19:24||schuylerhinman||New Issue|
|2018-08-03 19:24||schuylerhinman||File Added: wallHeatFluxBug_rhoCentralFOam.ods|
|2018-08-03 20:07||henry||Note Added: 0009895|
|2018-08-03 20:18||schuylerhinman||Note Added: 0009896|
|2018-08-03 20:32||henry||Note Added: 0009897|
|2018-08-03 20:36||schuylerhinman||Note Added: 0009898|
|2018-08-05 12:31||henry||Assigned To||=> henry|
|2018-08-05 12:31||henry||Status||new => resolved|
|2018-08-05 12:31||henry||Resolution||open => fixed|
|2018-08-05 12:31||henry||Fixed in Version||=> 6|
|2018-08-05 12:31||henry||Note Added: 0009902|