|
[Sponsors] |
![]() |
![]() |
#1 |
New Member
jhonny
Join Date: Oct 2013
Posts: 3
Rep Power: 13 ![]() |
Dear Foamers,
I am quite new to use OF to solve external aerodynamics. I am writing here to ask for your kind help. I try to simulate a cube placed on the ground on a face in order to understand how OF manage the force calculation with simpleFoam and with buoyantSimpleFoam. The point is that I should get the same value of forces on the cube, but something is wrong... I tried to compare the data in the postProcessing/forces folder with the value obtained by the integral of pressure on the cube's surfaces in paraFoam but i cant get the point. Maybe I make some mistakes: to integrate pressure on faces I generate surface normals on the cube and the integrate the calculated variable p*normals. The topics are these: 1. there is any differences on forceCalculation between simple and buoyant? 2. why the intergals of (p*normals) do not match with the force calculation of postProcessing folder? I'd like to thank anyone could help me... Here below there some values: /*___with simpleFoam___*/ P pressure 0; dimensions [0 2 -2 0 0 0 0]; --> after 50k iter forces(pressure, viscous, porous) (-1.677823966 -0.04192667675 0.8973219913) only pressure while with the integrateVariable on P 1.47393 -0.0309424 -0.895828 /*___withbuoyantSimpleFoam____*/ P pressure 101325; dimensions [1 -1 -2 0 0 0 0]; P_RGH pressure 100000; dimensions [1 -1 -2 0 0 0 0]; --> after 50k iter forces(pressure, viscous, porous) (-3.544135454 -0.2622319888 -24650.00027) only pressure while with the integrateVariable on P_rgh 193.717 421.979 26073.8 while with the integrateVariable on P 193.71 421.967 26072.3 |
|
![]() |
![]() |
![]() |
![]() |
#2 |
Senior Member
Nima Samkhaniani
Join Date: Sep 2009
Location: Tehran, Iran
Posts: 1,268
Blog Entries: 1
Rep Power: 25 ![]() |
look the dimensions of pressure in both solvers
![]()
__________________
My Personal Website (http://nimasamkhaniani.ir/) Telegram channel (https://t.me/cfd_foam) |
|
![]() |
![]() |
![]() |
![]() |
#3 |
New Member
jhonny
Join Date: Oct 2013
Posts: 3
Rep Power: 13 ![]() |
first of all, thanks for your reply.
I know that simpleFoam solve P/rho. The point is: why I obtain two different results with the two solvers for the same problem? moreover i don't understand why when I compare the Force pressure data in the postProcess folder with the integral of pressure done in paraFoam I can't get the same values. thanks |
|
![]() |
![]() |
![]() |
![]() |
#4 |
Senior Member
Nima Samkhaniani
Join Date: Sep 2009
Location: Tehran, Iran
Posts: 1,268
Blog Entries: 1
Rep Power: 25 ![]() |
about why this solvers return different results, as i said it returns to definition of pressure
![]() ![]() and about the second question, it returns how you calculate your values in paraView
__________________
My Personal Website (http://nimasamkhaniani.ir/) Telegram channel (https://t.me/cfd_foam) |
|
![]() |
![]() |
![]() |
![]() |
#5 |
Senior Member
Srivathsan N
Join Date: Jan 2013
Location: India
Posts: 101
Rep Power: 14 ![]() |
Hi Nima,
I would also like to know how results from buoyantBoussinesqSimpleFoam would compare with results from simpleFoam with buoyancy source term added to UEqn (similarly their unsteady counterparts). For similar settings, I can see that pressure is treated differently. For simpleFoam pressure is p/rho for incompressible case What changes should one make (in SimpleFoam) to get similar results in both?
__________________
Regards, Srivaths |
|
![]() |
![]() |
![]() |
Thread Tools | Search this Thread |
Display Modes | |
|
|
![]() |
||||
Thread | Thread Starter | Forum | Replies | Last Post |
interFoam vs. simpleFoam channel flow comparison | DanM | OpenFOAM Running, Solving & CFD | 12 | January 31, 2020 16:26 |
simpleFoam vs buoyantSimpleFoam | openFUser | OpenFOAM Post-Processing | 0 | February 3, 2014 12:13 |
Laminar simpleFoam and inviscid simpleFoam | herenger | OpenFOAM Running, Solving & CFD | 7 | July 11, 2013 07:27 |
Trying to run a benchmark case with simpleFoam | spsb | OpenFOAM | 3 | February 24, 2012 10:07 |
Naca0012 k-e mpirun gives fpe whereas simpleFoam not | Pierpaolo | OpenFOAM | 1 | May 8, 2010 04:08 |