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Saptarshi-Sarkar / OC3-Hywind-Spar

A MATLAB based package for dynamic simulation of spar-type floating offshore wind turbine.
Apache License 2.0
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Interpolation Error #5

Open Ian-Ammerman opened 6 months ago

Ian-Ammerman commented 6 months ago

Hi Saptarshi,

How are you? I am a master's student from the University of Maine, USA, working on floating wind turbine controls research. I am interested in using your simulation software in my work, but am having trouble debugging a particular issue.

I am running the default case from the Github - I generated wave data using the provided function with 0 elevation (still water condition) and generated a binary turbsim file similar to the example provided. I have attached the summary file below. All other inputs are the same as on the github. The simulation runs fine and is comparable to OpenFAST for as far as I can simulate; however, around 120 seconds into the simulation, I get the following error:

Lowest vertical interpolation point -100459450762629795099958394748928.000000 beyond grid. Increase grid height

Error in CheckInterpPoints (line 11)

    error('Lowest vertical interpolation point %f beyond grid. Increase grid height', min(ZBlNode_Y(:,iBd)));

Error in NominalSystemMatrix (line 314) CheckInterpPoints(WindNom.y, WindNom.z, ZBlNode_Y, ZBlNode_Z);

Error in SystemMatrices (line 111) [IM_nom, f_nom, Controls] = NominalSystemMatrix_mex(q_Nom, Controls, ElastoDyn, Airfoils, Twr, Bld, Platform, WindNom, mooring_load, f_Morison);

Error in RHS (line 4) [C,f,Controls] = SystemMatrices(t, q, Controls, DOFs, ElastoDyn, Airfoils, Twr, Bld, Platform, Wind, WindNom, wave, mooring_load_ptr, Servo);

Error in OffshoreWindTurbine>@(t,q,Controls)RHS(t,q,Controls,DOFs,ElastoDyn,Airfoils,Twr,Bld,Platform,Wind,WindNom,wave,mooring_load_ptr,Servo) (line 124) [q, Controls] = ode4(@(t,q,Controls) RHS(t, q, Controls, DOFs, ElastoDyn, Airfoils, Twr, Bld,...

Error in ode4 (line 25) [s2,Cons2] = F(t(i)+h/2, y+h*s1/2, Cons1);

Error in OffshoreWindTurbine (line 124) [q, Controls] = ode4(@(t,q,Controls) RHS(t, q, Controls, DOFs, ElastoDyn, Airfoils, Twr, Bld,...

Plotting the solution up to this point doesn't show any signs of numerical instability, and the large negative interpolation point is suspicious. Have you come across this issue before?

Best, Ian

8ms_OC3_Spar.txt

Ian-Ammerman commented 6 months ago

To add to this, the problem is avoided by uncommenting the steady wind line, so perhaps the issue is with the turbsim file or turbsim processor.