FAST v8 Rigid Simulations

Hello everyone,

is it possible to run FAST v8 rigid simulation ( = only use elastodyn, turn off all DOF) and still output the sectional force resultants (NβFxl) that are usually specified in the BeamDyn driver input file ? I am aware that I can use the Aerodyn force per unit length outputs (BαNβFl) but I thought there should be an easier way!

Best Regards,

Tobias

Dear Tobias,

Within FAST v8, ElastoDyn can be run with a rigid turbine, but BeamDyn cannot. In addition to the blade sectional load resultants output by BeamDyn (e.g. NβFxl), when BeamDyn is disabled, ElastoDyn can also output the blade sectional load resultants (e.g. SpnβFLxbα). AeroDyn’s blade load outputs are applied loads (e.g. BαNβFl), not reaction loads.

Best regards,

Hi Jason,

when I try to output the blade sectional load resultants I do not get any error messages during the simulation but in the unit specification of the corresponding output file “INVALID” appears. All values in the column are zero.
Concerning the output parameter SpnβFLxbα I assumed
β refers to blade section
x refers to coordinate direction
α refers to blade number.

Do you have any thoughts on what could be the cause of this ?

Best Regards,

Tobias

Dear Tobias,

Your understanding of output parameter SpnβFLxbα from ElastoDyn in FAST v8 is correct. These outputs will be invalid if BeamDyn is enabled or if β is greater than the number of output stations, NBlGages.

Best regards,