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#1 |
New Member
Jernej
Join Date: Sep 2011
Posts: 9
Rep Power: 15 ![]() |
Hi all,
I am interested in incorporating the effect of a propeller using rotorDiskSource class. I am using OpenFOAM-5.x. I have found a work (report and input files) by Capitao Patrao [Capitao Patrao, A.: Description and validation of the rotorDiskSource class for propeller performance estimation. In Proceedings of CFD with OpenSource Software, 2017, Edited by Nilsson. H., http://dx.doi.org/10.17196/OS_CFD#YEAR_2017] from the Chalmers University of Technology. The work gives a fix to the error in how the local forces are calculated and implements more general blade tip correction. I have successfully modified the original OF code. The corrected rotorDiskSource works without any problems when the solver (simpleFoam) is run in serial. However, the difficulties begin in parallel where the output is strange. Below I paste several outputs of rotorDisk. Serial case: rotorDisk output: min/max(AOA) = 1.6620832, 4.5369071 min/max(eps) = 25.235116, 59.281187 Rotor thrust = 671.50036 Rotor torque = 188.8365 Rotor power = 71041.172 Rotor propeller efficiency = 0.80412826 Effective drag = -576.07232 Effective lift = 671.50036 Parallel case (2 partitions): rotorDisk output: min/max(AOA) = 1.6619861, 4.5367581 min/max(eps) = 25.235298, 59.278707 Rotor thrust = 664.33664 Rotor torque = 186.83229 Rotor power = 70287.182 Rotor propeller efficiency = 0.80408372 Effective drag = -576.0604 Effective lift = 671.48486 Parallel case (3 partitions): rotorDisk output: min/max(AOA) = 1.6621062, 4.5363851 min/max(eps) = 5.729578e+16, -5.729578e+16 Rotor thrust = 0 Rotor torque = 0 Rotor power = 0 Rotor propeller efficiency = nan Effective drag = -576.04504 Effective lift = 671.45967 Parallel case (6 partitions): rotorDisk output: min/max(AOA) = 1.6617572, 4.5364101 min/max(eps) = 25.235737, 45.521711 Rotor thrust = 186.92322 Rotor torque = 52.674087 Rotor power = 19816.238 Rotor propeller efficiency = 0.80247451 Effective drag = -576.03327 Effective lift = 671.44934 Does anybody have some experience in fixing the issue and can give a piece of advice? Thank you. Jernej |
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#2 |
Member
Jeff
Join Date: May 2016
Posts: 44
Rep Power: 10 ![]() |
I had experiments with case running in serial and posing problem in parallel when using ggi coupling interface.
In my case it was traced back to a bug in openmpi implementation I have no idea if your problem is of the same kind though Can you post the case? JF |
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#3 |
New Member
Jernej
Join Date: Sep 2011
Posts: 9
Rep Power: 15 ![]() |
Hi Jeff,
I am using the original case (prop_incomp_refCase) as described in Proceedings of CFD with OpenSource Software, 2017 (Edited by Nilsson H. http://dx.doi.org/10.17196/OS_CFD#YEAR_2017). Following the link the case files can be downloaded. Angle of attack, effective lift and drag are invariant to the number of partitions (as expected). What bothers me is that eps, rotor thrust, torque, power, and propeller efficiency are not ![]() Regards, Jernej |
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#4 |
Member
Luis Eduardo
Join Date: Jan 2011
Posts: 85
Rep Power: 15 ![]() |
How does your flow field look like?
If you generate a slice in one of the rotor planes for all the cases you are running, do they look the same? It may be just a matter of taking the information from all the processors for the calculation of the variables (usually the sumop() - or something like this - part of the code) Try the slices, check if the physics make sense. Best Regards, Luis |
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#5 |
New Member
Aleksei
Join Date: Oct 2016
Posts: 4
Rep Power: 9 ![]() |
Hi!
I have a very similar experience using rotorDisk. Like you, I successfully modified the original OF code using Capitao Report. Anyway with corrections or without rotorDisk dont work adequately. Besides problems with parallel run, there are also some oscillation when run simpleFoam in serial. Oscillation in rotor forces generate oscillation in field U which leads to resonance (it`s my explanation ![]() You can see how it look like in slice through the rotor (colored by force magnitude). https://www.youtube.com/watch?v=D7cN2Dcwixw https://www.youtube.com/watch?v=zQzQw7gU5XE It was observed in case similar to tutorials simpleFoam/rotorDisk, was slightly changed mesh only. I managed to get rid of oscillations by decreasing the relaxation factor U to 0.45. Maybe its not good method? Have anyone thoughts about the reason of this strange phenomena? |
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#6 |
New Member
Join Date: May 2019
Posts: 5
Rep Power: 7 ![]() |
Hi !
I think I solved the issue ! With OF1812 and using the same files and following the same report. I tried several decompositions of the case using SIMPLE method, in decomposeParDict I have for example : Code:
numberOfSubdomains 3; method simple; simpleCoeffs { n (1 3 1); delta 0.001; } n (1 1 1) (undecomposed, reference) Code:
rotorDisk output: min/max(AOA) = 1.6603615, 4.5343289 min/max(eps) = 25.238325, 59.282909 Rotor thrust = 671.04952 Rotor torque = 188.71667 Rotor power = 70986.411 Rotor propeller efficiency = 0.80420828 Effective drag = -575.71016 Effective lift = 671.04952 Code:
rotorDisk output: min/max(AOA) = 1.660361, 4.5343286 min/max(eps) = 25.238325, 59.282909 Rotor thrust = 335.52474 Rotor torque = 94.358332 Rotor power = 35493.204 Rotor propeller efficiency = 0.80420828 Effective drag = -575.71012 Effective lift = 671.0494 Code:
rotorDisk output: min/max(AOA) = 1.6603613, 4.5343287 min/max(eps) = 25.238325, 59.282909 Rotor thrust = 167.76238 Rotor torque = 47.179168 Rotor power = 17746.603 Rotor propeller efficiency = 0.80420828 Effective drag = -575.71014 Effective lift = 671.0495 Code:
rotorDisk output: min/max(AOA) = 1.6603616, 4.534329 min/max(eps) = 25.238325, 59.282909 Rotor thrust = 274.3083 Rotor torque = 77.168146 Rotor power = 29027.057 Rotor propeller efficiency = 0.80394276 Effective drag = -575.71017 Effective lift = 671.04953 n (1 3 1) Code:
min/max(AOA) = 4.0015841, 7.9121525 min/max(eps) = 5.729578e+16, -5.729578e+16 Rotor thrust = 0 Rotor torque = 0 Rotor power = 0 Rotor propeller efficiency = Code:
[v501:32819] *** Process received signal *** [v501:32819] Signal: Floating point exception (8) [v501:32819] Signal code: (-6) [v501:32819] Failing at address: 0x3ef00008033 [v501:32819] [ 0] /lib/x86_64-linux-gnu/libc.so.6(+0x354b0)[0x7f32e132d4b0] [v501:32819] [ 1] /lib/x86_64-linux-gnu/libc.so.6(gsignal+0x38)[0x7f32e132d428] [v501:32819] [ 2] /lib/x86_64-linux-gnu/libc.so.6(+0x354b0)[0x7f32e132d4b0] [v501:32819] [ 3] /home/cfd/OpenFOAM/cfd-v1812/platforms/linux64GccDPInt32Opt/lib/libfvOptions.so(_ZNK4Foam2fv15rotorDiskSource9calculateINS_17geometricOneFieldEEEvRKT_RKNS_5FieldINS_6VectorIdEEEERKNS7_IdEERSA_bb+0xd5a)[0x7f32e3a3120a] [v501:32819] [ 4] /home/cfd/OpenFOAM/cfd-v1812/platforms/linux64GccDPInt32Opt/lib/libfvOptions.so(_ZN4Foam2fv15rotorDiskSource6addSupERNS_8fvMatrixINS_6VectorIdEEEEi+0x396)[0x7f32e3a2d476] [v501:32819] [ 5] simpleFoam[0x444659] [v501:32819] [ 6] simpleFoam[0x420603] [v501:32819] [ 7] /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xf0)[0x7f32e1318830] [v501:32819] [ 8] simpleFoam[0x423f29] [v501:32819] *** End of error message *** Yes !! It's seems to be it ! I propose this modification in the file RotorDiskSourceTemplates.C (search for '//NEW MODIFICATION') : Code:
//scalar etaProp = thrustEff*refVelEta_/powerEff; //NEW LINE //NEW MODIFICATION comment this as it can result in a division by 0 if (output) { reduce(AOAmin, minOp<scalar>()); reduce(AOAmax, maxOp<scalar>()); reduce(dragEff, sumOp<scalar>()); reduce(liftEff, sumOp<scalar>()); reduce(epsMin, minOp<scalar>());//vlhomme 02/09/2019 MODIFICATION reduce(epsMax, maxOp<scalar>());//vlhomme 02/09/2019 MODIFICATION reduce(thrustEff, sumOp<scalar>());//vlhomme 29/08/2019 MODIFICATION reduce(torqueEff, sumOp<scalar>());//vlhomme 29/08/2019 MODIFICATION reduce(powerEff, sumOp<scalar>()); //vlhomme 29/08/2019 MODIFICATION scalar etaProp = thrustEff*refVelEta_/powerEff; //vlhomme 29/08/2019 MODIFICATION : I add this line cause here there is no risk of division by 0 Info<< type() << " output:" << nl << " min/max(AOA) = " << radToDeg(AOAmin) << ", " << radToDeg(AOAmax) << nl << " min/max(eps) = " << radToDeg(epsMin) << ", " //NEW LINE << radToDeg(epsMax) << nl //NEW LINE << " Rotor thrust = " << thrustEff << nl //NEW LINE << " Rotor torque = " << torqueEff << nl //NEW LINE << " Rotor power = " << powerEff << nl //NEW LINE << " Rotor propeller efficiency = " << etaProp << nl //NEW LINE << " Effective drag = " << dragEff << nl << " Effective lift = " << liftEff << endl; } } ![]() Last edited by vLhomme; September 2, 2019 at 06:10. |
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#7 |
Senior Member
Farzad Faraji
Join Date: Nov 2019
Posts: 206
Rep Power: 7 ![]() |
Dear Friends
I want to use rotorDisk example in my case which is a lagrangian solver(I have already added fvOptions and I can add external momentum sources). according to the code; https://github.com/OpenFOAM/OpenFOAM...stem/fvOptions which I copied here; Code:
/*--------------------------------*- C++ -*----------------------------------*\ ========= | \\ / F ield | OpenFOAM: The Open Source CFD Toolbox \\ / O peration | Website: https://openfoam.org \\ / A nd | Version: 6 \\/ M anipulation | \*---------------------------------------------------------------------------*/ FoamFile { version 2.0; format ascii; class dictionary; object fvOptions; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // disk { type rotorDisk; selectionMode cellZone; cellZone rotatingZone; fields (U); // Names of fields on which to apply source nBlades 3; // Number of blades tipEffect 0.96; // Normalised radius above which lift = 0 inletFlowType local; // Inlet flow type specification inletVelocity (0 1 0); geometryMode specified; origin (0 0 0); axis (0 1 0); refDirection (0 0 1); // Reference direction // - used as reference for psi angle rpm 1000; // pointAbove (0 0 0.25); trimModel fixedTrim; // fixed || targetForce rhoRef 1000; rhoInf 1; fixedTrimCoeffs { theta0 0; theta1c 0; theta1s 0; } flapCoeffs { beta0 0; // Coning angle [deg] beta1c 0; // Lateral flapping coeff (cos coeff) beta2s 0; // Longitudinal flapping coeff (sin coeff) } blade { data ( (profile1 (0.1 -6 0.02)) (profile1 (0.25 -6 0.02)) ); } profiles { profile1 { type lookup; data ( (-90 0.21 1.45) (-18 0.21 1.45) (-16 0.165 1.3) (-14 0.125 1.1) (-12 0.092 0.95) (-10 0.07 0.8) (-8 0.05 0.64) (-6 0.04 0.5) (-4 0.028 0.32) (-2 0.022 0.18) (0 0.02 0) (2 0.022 0.18) (4 0.028 0.32) (6 0.04 0.5) (8 0.05 0.64) (10 0.07 0.8) (12 0.092 0.95) (14 0.125 1.1) (16 0.165 1.3) (18 0.21 1.45) (90 0.21 1.45) ); } } } // ************************************************************************* // I can add effect of blades in my simulation, but I can't and I can not see any effect. can anyone help me? Thanks, Farzad Using rotorDisk(or any other blade simulator) for mixing purpose by applying fvOption |
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#8 |
Member
Join Date: Apr 2021
Posts: 41
Rep Power: 5 ![]() |
Many thanks vLhomme for the fix you proposed.
Have you managed to make this working with OFv2112 as well ? From my side, following the same files and report, it seems there is now something wrong when compiling. |
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Tags |
openfoam 5.x, propeller, rotordisksource |
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