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IDProjectCategoryView StatusLast Update
0002609OpenFOAM[All Projects] Bugpublic2018-07-10 11:24
ReporterSvensenAssigned Tohenry 
PrioritynormalSeveritymajorReproducibilityalways
Status closedResolutionno change required 
PlatformGNU/LinuxOSUbuntuOS Version14.04
Product Versiondev 
Fixed in Version 
Summary0002609: SIMPLE and SIMPLEC produce different results
DescriptionI've tested a SIMPLEC vs SIMPLE algorithms for my simulation and found that SIMPLEC produced a significantly higher velocities compared to SIMPLE.

The case was the same. The only things that were changed were:
1) consistent yes;
2) no relaxation for pressure; relaxation for velocity 0.9

A screenshot with comparative cross-sections is attached.

From my own experience I could say that result with SIMPLE seems to be correct.
But why SIMPLEC gives a different result ?

I can upload the case if it is necessary.
Tagssimplec

Activities

Svensen

2017-07-10 21:00

reporter  

SIMPLE_vs_SIMPLEC.png (220,203 bytes)
SIMPLE_vs_SIMPLEC.png (220,203 bytes)

wyldckat

2017-07-11 01:29

updater   ~0008379

I'm not familiar with how SIMPLEC works, what are the expectable results and the settings that are meant to be used... but there is at least one important detail that is missing in this report: What about the residuals?

And the follow up questions: What do the residual plots look like? Did both simulations really converge? Or did you simply let it run only for X iterations and assume it converged?


Beyond this, your report is looking too much like a support request, than a bug report. Please follow the instructions given here: https://bugs.openfoam.org/rules.php

Svensen

2017-07-11 20:04

reporter  

simple_residuals.png (16,315 bytes)
simple_residuals.png (16,315 bytes)

Svensen

2017-07-11 20:04

reporter  

simple_continuity.png (14,459 bytes)
simple_continuity.png (14,459 bytes)

Svensen

2017-07-11 20:05

reporter  

simplec_residuals.png (17,717 bytes)
simplec_residuals.png (17,717 bytes)

Svensen

2017-07-11 20:05

reporter  

simplec_continuity.png (15,864 bytes)
simplec_continuity.png (15,864 bytes)

Svensen

2017-07-11 20:05

reporter   ~0008382

The residual plots are attached.
It is a pulsatile flow with pulse period of 0.77 s. I've simulated 5 full periods.

OK, I will post this topic on cfd-online.com tomorrow.

henry

2017-07-11 20:28

manager   ~0008383

User support request

Issue History

Date Modified Username Field Change
2017-07-10 21:00 Svensen New Issue
2017-07-10 21:00 Svensen File Added: SIMPLE_vs_SIMPLEC.png
2017-07-10 21:00 Svensen Tag Attached: openfoam-dev
2017-07-10 21:00 Svensen Tag Attached: simplec
2017-07-11 01:29 wyldckat Note Added: 0008379
2017-07-11 20:04 Svensen File Added: simple_residuals.png
2017-07-11 20:04 Svensen File Added: simple_continuity.png
2017-07-11 20:05 Svensen File Added: simplec_residuals.png
2017-07-11 20:05 Svensen File Added: simplec_continuity.png
2017-07-11 20:05 Svensen Note Added: 0008382
2017-07-11 20:28 henry Assigned To => henry
2017-07-11 20:28 henry Status new => closed
2017-07-11 20:28 henry Resolution open => no change required
2017-07-11 20:28 henry Note Added: 0008383
2018-07-10 11:24 administrator Tag Detached: openfoam-dev