|
[Sponsors] |
May 31, 2023, 06:40 |
Motorbike Tutorial Error: coeffs=0
|
#1 |
New Member
L T
Join Date: May 2023
Posts: 1
Rep Power: 0 |
Hey there,
i'm getting into OpenFoam (using OF10) and after following few of József Nagy tutorials (god bless this guy) i tried some stuff myself, everything kinda worked until i tried the motorbike tutorial. here's the link: https://www.youtube.com/watch?v=1C4Av_yCfpw I tried multiple times following the tutorials i foun on YT etc, but no results. the mesh seems fine, i don't get any error and i can see it using paraview. it seems like there is something wrong either with the initial conditions or with the solver, as at every iteration i get CD, CL, CM all equal to 0 (the velocity is the pre defined 20m/s value). after building the mesh (blockmesh + surfaceFeatures + snappyHexMesh) and checking with the dummy file in paraview that the mesh is there, i copied everything that's in folder 0 to folder 3 (replacing what is with the same name) then launching the simulation with simpleFoam, that's the result: Cm=0 Cd=0 Cl=0 Cl(f)=0 Cl(r)=0 also it seems that the simulation does not converge, as when solving for Ux, it reaches 1000 iterations and then moves on (attached image). of course when opening paraview, i don't see any pressure or velocity field. Also, when opening the U or P files, they look weird, likely they are somehow corrupt or something. it's probably some extremely dumb mistake i'm making, but really cant figure it out! Attacched: snappyHexMesh terminal printout simpleFoam terminal printout end simulation terminal printout last timestep result folder initial conditions (made up) folder initial_conditions.zip 500.zip Screenshot from 2023-05-31 12-18-07.png Screenshot from 2023-05-31 12-09-44.png Screenshot from 2023-05-31 12-06-36.png Last edited by TAZ; May 31, 2023 at 07:06. Reason: some files unavailable |
|
August 24, 2023, 13:58 |
Did you find any solution to this?
|
#2 |
New Member
Adam
Join Date: Aug 2023
Posts: 2
Rep Power: 0 |
Same issue
Checked initial condition , p and U files still no change, all coefficients values are 0. Last edited by cfd_site_m; September 2, 2023 at 02:33. |
|
September 2, 2023, 02:42 |
Solved
|
#3 |
New Member
Adam
Join Date: Aug 2023
Posts: 2
Rep Power: 0 |
Number of cells/points in mesh and field don't match
I followed solution by aghora17 1: surfaceFeatureExtract 2:blockMesh 3: In controldict file set the startfrom to latestTime 4: copy polymesh, p,U,k, nut and omega files to dir 1,2 and 3. (do not replace them the existing ones just paste the ones that don't exist) (extendedFeatureEdgeMesh as well if you are facing issue) From what I could gather the issue is number of cell discrepancy. And it's supposed to skip the step 0 during solving case and solve from latestTime. Openfoam v6 has startfrom set to laterTime but openfoam v11 has set it to startTime so it'll start from 0. Also change the 0 file from 0.orig to 0 |
|
September 5, 2023, 09:05 |
|
#4 |
New Member
Federico Nahuel Ramírez
Join Date: Dec 2020
Location: Spain
Posts: 16
Rep Power: 5 |
Hi,
Have you tried using the "-overwrite" flag when meshing instead of copying the data from one folder to another? It would be: snappyHexMesh -overwriteThen you should have the mesh in the polyMesh folder in constant instead of at new "iteration" folders. If this doesn't work I would take a look at the name of the boundaries (at polyMesh or using paraview) and then check de initial conditions and forceCoeffs dictionary. |
|
Tags |
motorbike tutorial, openfoam 10 |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
flowVelocity and drag coefficient issue in the motorBike tutorial | jan90300 | OpenFOAM Running, Solving & CFD | 3 | April 28, 2021 01:22 |
Choosing l in external aero simulation & nu used in motorbike tutorial | edomalley1 | OpenFOAM Running, Solving & CFD | 0 | November 28, 2017 12:39 |
[snappyHexMesh] How to eliminate skew faces in motorbike tutorial | sharkbait_au | OpenFOAM Meshing & Mesh Conversion | 2 | July 17, 2015 11:54 |
[snappyHexMesh] Proper y+ in boundary layer on lowerWall - motorBike tutorial | petr.f. | OpenFOAM Meshing & Mesh Conversion | 2 | June 9, 2015 05:47 |
[snappyHexMesh] Tweaked motorbike tutorial doesn't show my icosphere | mfiandor | OpenFOAM Meshing & Mesh Conversion | 0 | October 9, 2011 18:39 |