BeamDyn bug fixes and updates

[rafmudaf]

This pull request will merge significant updates to BeamDyn developed at Envision Energy. These updates have been tested and validated as shown below.

The following updates are included:

• The load initialization scheme is improved in the static routine at commit 80c28d9
• These GitHub issues are resolved:
  • Local Sectional Load (Force/Moment) Output Bug in BeamDyn #11
  • BeamDyn initialization with non-zero initial azimuth produces strange results #26

Issue 11

Sectional load calculations are fixed in commit 0829f84 at line 1569.

This issue is exposed by evaluating the results of the BeamDyn regression test case 5MW_Land_BD_DLL_WTurb. In the OpenFAST dev branch, the first node is at the root but the sectional loads do not match the root loads. Furthermore, the BeamDyn sectional loads do not match the ElastoDyn sectional loads. In this case, the blade root has 13.3 degrees of structural twist so the difference in loads between section 1 and root is related to the offset coordinate systems between blade local and blade reference.

The charts below compare the solutions of the NREL 5MW turbine regression test cases with ElastoDyn and BeamDyn. The left and right columns (ElastoDyn and BeamDyn solutions, respectively) are expected to match. The charts in the upper and lower rows (root and first section, respectively) are expected to differ in magnitude. However, a difference in the ElastoDyn and BeamDyn solution is clearly shown.

Note the difference in units: N vs kN.

The updated BeamDyn solutions demonstrate agreement between the sectional and root loads and are validated by ElastoDyn.

The OpenFAST regression test case using BeamDyn, 5MW_Land_BD_DLL_WTurb, does not currently output the sectional loads, so this bug was not exposed there and it does not require an updated baseline solution. However, the BeamDyn specific regression test bd_5MW_dynamic does require an update to the baselines as the sectional loads have been updated. The root and node 1 forces and moments are shown side by side with the corrected BeamDyn solutions below.

Issue 26

Initial translational velocity calculation is fixed at commit 97d1c2a.

The problems is exposed by running 5MW_Land_BD_DLL_WTurb with initial azimuth angle 0 and 120 from the OpenFAST dev branch. With an initial azimuth of 120 degrees, it is expected that the root moments would simply shift blade numbers in this pattern:

• Blade 1 at azimuth 0 -> Blade 3 at azimuth 120
• Blade 2 at azimuth 0 -> Blade 1 at azimuth 120
• Blade 3 at azimuth 0 -> Blade 2 at azimuth 120

The solution from openfast/dev is shown in the charts below where the root moments do not shift as expected and a frequency variation is introduced in the rotor torque.

The following charts show that this pull request fixes the root moment blade shift and calculates a consistent rotor torque.

[rafmudaf]

@ghaymanNREL in response to your question in an earlier pull request (#109) regarding the openfast-related regression tests, here are the results from peregrine. As expected, the only failing case is the BeamDyn associated case.

[rmudafor@login2 reg_tests]$ python3 manualRegressionTest.py ../build/glue-codes/fast/openfast linux intel 1e-5 -n
executing AWT_YFix_WSt                           PASS
executing AWT_WSt_StartUp_HighSpShutDown         PASS
executing AWT_YFree_WSt                          PASS
executing AWT_YFree_WTurb                        PASS
executing AWT_WSt_StartUpShutDown                PASS
executing AOC_WSt                                PASS
executing AOC_YFree_WTurb                        PASS
executing AOC_YFix_WSt                           PASS
executing UAE_Dnwind_YRamp_WSt                   PASS
executing UAE_Upwind_Rigid_WRamp_PwrCurve        PASS
executing WP_VSP_WTurb_PitchFail                 PASS
executing WP_VSP_ECD                             PASS
executing WP_VSP_WTurb                           PASS
executing WP_Stationary_Linear                   PASS
executing SWRT_YFree_VS_EDG01                    PASS
executing SWRT_YFree_VS_EDC01                    PASS
executing SWRT_YFree_VS_WTurb                    PASS
executing 5MW_Land_DLL_WTurb                     PASS
executing 5MW_OC3Mnpl_DLL_WTurb_WavesIrr         PASS
executing 5MW_OC3Trpd_DLL_WSt_WavesReg           PASS
executing 5MW_OC4Jckt_DLL_WTurb_WavesIrr_MGrowth PASS
executing 5MW_ITIBarge_DLL_WTurb_WavesIrr        PASS
executing 5MW_TLP_DLL_WTurb_WavesIrr_WavesMulti  PASS
executing 5MW_OC3Spar_DLL_WTurb_WavesIrr         PASS
executing 5MW_OC4Semi_WSt_WavesWN                PASS
executing 5MW_Land_BD_DLL_WTurb                  FAIL

[rafmudaf]

The regression test baseline solutions have been updated for all supported platform/compiler combinations. After review, this pull request can be merged.

[jjonkman]

Looks good to me. Thanks.