Harp_Opt for small scale Tidal Rotor

Hi Folks,

I was wondering if anyone knew if there was a minimum size of rotor that Harp_Opt can give reasonable results for. My problem is that when I try to design a rotor of 12cm diameter, the water depth must be at least 3m before it will run or I get an error message reading…

??? Error using ==>times
Matrix dimensions must agree.

Error in ==> Main at 128
OmgCC = TSR_Opt.*V.*30/(pi.*RotorRad);

Error in ==> gaCustom_Creation at 212
F = Main(X);

Error in ==> makeState at 31
state.Population =
feval(options.CreationFcn,GenomeLength,FitnessFcn,options,options.CreationFcnArgs{:});

Error in ==> galincon at 18
state = makeState(GenomeLength,FitnessFcn,Iterate,output.problemtype,options);

Error in ==> ga at 306
[x,fval,exitFlag,output,population,scores] = galincon(FitnessFcn,nvars,

Error in ==> HARP_Opt>Optimize_Callback at 828
[x_final] = ga(@Main,NumVars,A,b,[],[],LB,UB,[],GAoptions);

Error in ==> gui_mainfcn at 96
feval(varargin{:});

Error in ==> HARP_Opt at 47
gui_mainfcn(gui_State, varargin{:});

Error in ==>
@(hObject,eventdata)HARP_Opt(‘Optimize_Callback’,hObject,eventdata,guidata(hObject))

??? Error while evaluating uicontrol Callback

When I do manage to get the code to run with reasonable water depth, the blade it creates has a less than desirable power curve. Is HARP_Opt primarily optimised for large scale devices? or should it spit out good results for small scale also?

Hi Kristian,

HARP-Opt should work for small turbines. I’ll be happy to take a look at your problem if you send me the input files.

Cheers,

-Mike

Michael J. Lawson, Ph.D.
Postdoctoral Researcher
National Renewable Energy Laboratory
www.nrel.gov

Thanks Michael, email sent!!

Just for information everyone,

I have been trying to optimise a 1/16th scale model of a 3m hydrorotor for tow tank testing with the NACA 6412 (Low Re no. data available) foil and kept getting the error above or an error saying there was something wrong with the “strainLE” variable. Over time I noticed it sometimes worked and sometimes didn’t.

I have just realised that if I run Harp_Opt with multiple foil thicknesses (e.g. FFA 30 24 21), cancel it, and then revert to my single NACA 6412, it will run fine with no error messages. I do not know why this is, but I am quite happy that I have some sort of solution to my problem.

I would love to hear from anyone that can explain this phenomenon to me. I have a distinct feeling that I am doing something totally stupid!! haha

Cheers

Kristian