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The problem may relate to the failure to initialise deltaT from the previous run during restart of cases with variable time-step. This issue is resolved by
commit 6355c656034dba7648b32c16e899a8dbd3dbf211
Please could you test this change on your case and report back. |
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Ok, I will test it and report back as soon as I can |
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I've compiled the modified Time.C file and run a new test, but there seems to be no significant changes (see the new plot attached: in red there is the restart with the new Time.C file, in blue the old one) |
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Could you check if the deltaT is now initialised correctly on restart, i.e is the deltaT for the first two time-steps after restart the same as for the corresponding run without restart?
So far I have not managed to reproduce your problem, could you send a small test-case which reproduces is? |
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About the deltaT's, they seem to be initalized correctly (see the files attached called restart and no_restart). About the test case, I'll need some time to build a smaller one (alternatively I can send you the valve case, but I doubt it's small enough for your purposes, as it is an about 90k cells 2D domain) |
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restart (3,626 bytes)
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Create time
Create mesh for time = 0.008
Reading thermophysical properties
Selecting thermodynamics package ePsiThermo<pureMixture<constTransport<specieThermo<eConstThermo<perfectGas>>>>>
Reading field U
Creating turbulence model
Selecting turbulence model type RASModel
Selecting RAS turbulence model SpalartAllmaras
SpalartAllmarasCoeffs
{
sigmaNut 0.66666;
kappa 0.41;
Prt 1;
Cb1 0.1355;
Cb2 0.622;
Cw2 0.3;
Cw3 2;
Cv1 7.1;
Cv2 5;
}
Reading thermophysicalProperties
fluxScheme: Tadmor
Starting time loop
Mean and max Courant Numbers = 0.0116665509 0.4794822217
deltaT = 5.06636944e-08
Time = 0.0080000507
diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
diagonal: Solving for rhoUx, Initial residual = 0, Final residual = 0, No Iterations 0
diagonal: Solving for rhoUy, Initial residual = 0, Final residual = 0, No Iterations 0
smoothSolver: Solving for Ux, Initial residual = 3.750210016e-06, Final residual = 1.614790165e-11, No Iterations 4
smoothSolver: Solving for Uy, Initial residual = 2.251666888e-05, Final residual = 1.254103204e-12, No Iterations 6
diagonal: Solving for rhoE, Initial residual = 0, Final residual = 0, No Iterations 0
smoothSolver: Solving for e, Initial residual = 1.919391474e-06, Final residual = 6.572060701e-12, No Iterations 4
smoothSolver: Solving for nuTilda, Initial residual = 1.711501306e-05, Final residual = 1.632811743e-12, No Iterations 6
ExecutionTime = 0.27 s ClockTime = 1 s
Mean and max Courant Numbers = 0.01216528503 0.4897796449
deltaT = 5.171711351e-08
Time = 0.0080001024
diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
diagonal: Solving for rhoUx, Initial residual = 0, Final residual = 0, No Iterations 0
diagonal: Solving for rhoUy, Initial residual = 0, Final residual = 0, No Iterations 0
smoothSolver: Solving for Ux, Initial residual = 3.825730737e-06, Final residual = 1.750776668e-11, No Iterations 4
smoothSolver: Solving for Uy, Initial residual = 2.296748584e-05, Final residual = 1.396263204e-12, No Iterations 6
diagonal: Solving for rhoE, Initial residual = 0, Final residual = 0, No Iterations 0
smoothSolver: Solving for e, Initial residual = 1.957642157e-06, Final residual = 7.120802639e-12, No Iterations 4
smoothSolver: Solving for nuTilda, Initial residual = 1.731406049e-05, Final residual = 1.836024872e-12, No Iterations 6
ExecutionTime = 0.43 s ClockTime = 1 s
Mean and max Courant Numbers = 0.01241824786 0.5115560873
deltaT = 5.054576534e-08
Time = 0.0080001529
diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
diagonal: Solving for rhoUx, Initial residual = 0, Final residual = 0, No Iterations 0
diagonal: Solving for rhoUy, Initial residual = 0, Final residual = 0, No Iterations 0
smoothSolver: Solving for Ux, Initial residual = 3.73340873e-06, Final residual = 1.548896449e-11, No Iterations 4
smoothSolver: Solving for Uy, Initial residual = 2.240229571e-05, Final residual = 1.17744566e-12, No Iterations 6
diagonal: Solving for rhoE, Initial residual = 0, Final residual = 0, No Iterations 0
smoothSolver: Solving for e, Initial residual = 1.908762884e-06, Final residual = 6.293642794e-12, No Iterations 4
smoothSolver: Solving for nuTilda, Initial residual = 1.681234368e-05, Final residual = 1.561274453e-12, No Iterations 6
ExecutionTime = 0.59 s ClockTime = 1 s
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no_restart (3,076 bytes)
Mean and max Courant Numbers = 0.0116665431063994 0.46937095453393
deltaT = 4.85866084726227e-08
Time = 0.008
diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
diagonal: Solving for rhoUx, Initial residual = 0, Final residual = 0, No Iterations 0
diagonal: Solving for rhoUy, Initial residual = 0, Final residual = 0, No Iterations 0
smoothSolver: Solving for Ux, Initial residual = 3.59506041072506e-06, Final residual = 1.32648247420957e-11, No Iterations 4
smoothSolver: Solving for Uy, Initial residual = 2.15719408775685e-05, Final residual = 9.58393312965961e-13, No Iterations 6
diagonal: Solving for rhoE, Initial residual = 0, Final residual = 0, No Iterations 0
smoothSolver: Solving for e, Initial residual = 1.83747338122507e-06, Final residual = 5.3955008222507e-12, No Iterations 4
smoothSolver: Solving for nuTilda, Initial residual = 5.99354006957163e-06, Final residual = 1.34288728666557e-12, No Iterations 4
ExecutionTime = 14757.47 s ClockTime = 14774 s
Mean and max Courant Numbers = 0.0116665509017334 0.479482221729818
deltaT = 5.06636943965954e-08
Time = 0.00800005066
diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
diagonal: Solving for rhoUx, Initial residual = 0, Final residual = 0, No Iterations 0
diagonal: Solving for rhoUy, Initial residual = 0, Final residual = 0, No Iterations 0
smoothSolver: Solving for Ux, Initial residual = 3.75021001608965e-06, Final residual = 1.61479016895789e-11, No Iterations 4
smoothSolver: Solving for Uy, Initial residual = 2.25166677336211e-05, Final residual = 1.25410360037952e-12, No Iterations 6
diagonal: Solving for rhoE, Initial residual = 0, Final residual = 0, No Iterations 0
smoothSolver: Solving for e, Initial residual = 1.91939147350145e-06, Final residual = 6.57205940965516e-12, No Iterations 4
smoothSolver: Solving for nuTilda, Initial residual = 6.25122489696877e-06, Final residual = 1.56428036027479e-12, No Iterations 4
ExecutionTime = 14757.74 s ClockTime = 14774 s
Mean and max Courant Numbers = 0.0121652850286103 0.4897796448567
deltaT = 5.17171135104587e-08
Time = 0.00800010238
diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
diagonal: Solving for rhoUx, Initial residual = 0, Final residual = 0, No Iterations 0
diagonal: Solving for rhoUy, Initial residual = 0, Final residual = 0, No Iterations 0
smoothSolver: Solving for Ux, Initial residual = 3.83014581439549e-06, Final residual = 1.77866606190746e-11, No Iterations 4
smoothSolver: Solving for Uy, Initial residual = 2.29999625765836e-05, Final residual = 1.4307470880081e-12, No Iterations 6
diagonal: Solving for rhoE, Initial residual = 0, Final residual = 0, No Iterations 0
smoothSolver: Solving for e, Initial residual = 1.96046340934368e-06, Final residual = 7.24063691716022e-12, No Iterations 4
smoothSolver: Solving for nuTilda, Initial residual = 6.38166789162216e-06, Final residual = 1.70945191413511e-12, No Iterations 4
ExecutionTime = 14757.89 s ClockTime = 14775 s
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Here it is a smaller version of my valve case (the mesh around the valve is exactly the same, but the domain is about 3 times smaller). To check the behavior I am talking about, you can do the following steps:
-first run the case for 0.003 s;
-then restart it from 0.0015 s and again till 0.003 s;
-plot the torque values calculated by the forces function in the two cases and see the difference between them.
Some additional notes:
1) the z axis pressure-related torque output is printed as the 10th column of the forces.dat output file (viscous forces are negligible for this case if compared to the pressure-related ones);
2) I run this case in parallel, on the 4 cores of my intel i7 laptop, and it took me about 1h10 min from 0 to 0.003 s (anyway, I'm quite sure you can shorten a bit the simulation time, e. g. to 0.002 s with the restart at 0.001 s).
Hope this helps to find out where the problem is |
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I am unable to run your case, it apears that many of the files are out of date. Could you upgrade it to OpenFOAM-2.0.x, see if the restart problem persists and if so post the updated case here for us to investigate. |
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Well, I am an OF-1.7.x user (as clearly stated in my initial report), so I would like to know if there is a bug in that version and not only in the latest release (and I think that this matter could be of interest for many users which, as myself, have put a lot of development work in the older releases and don't want to upgrade all of their additional code only to fix a single bug). Anyway, I will try to update the case in a OF-2.0.x-consistent format and resend it as soon as I can.
Regards |
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Here it is the same test case, but adapted to work with with OF-2.0.x: I've tried it with OF-2.0.1 and the behavior is exactly the same as encountered in OF-1.7.x. To check it, follow the instructions previously posted. |
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Thanks. The problem should be resolved by
commit dc17e722ab2a9539775eec59650e6dc0e7eb9360
in OpenFOAM-2.0.x, could you pull it and test your case again? |
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Ok, I'll try the fix and report back |
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I've tried the changes in commit dc17e722ab2a9539775eec59650e6dc0e7eb9360 on OF-2.0.1 and the problem seems fixed: as you can see from the new plot attached, now the no-dump and dumped run return consistent torque values (it is also interesting to underline how the plotted value is significantly different from the old implementation, either with and without restarting, which means that with the old one an error propagated through time and affected the final solution)
Regards |
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