Troubleshooting, Parametrization, and Design

Professor Christiani

11/17/2014

Goals Troubleshooting:

Ensure your code is running properly Parametrizing:

Develop a strategy for optimization Other considerations:

Design setup Report

Troubleshooting

What should the output look like?

Small pitch angle

What should the output look like?

Large pitch angle

How to Debug MATLAB will tell you exactly where the

problem is! Observe what line the error is in Understand what the error is saying

Common problems include: Undefined variables (N, c, or β is blank) Crazy graphs! (W instead of ω) Incomplete loops (‘for’ but no ‘end’) Others?

Ask us to help you!

Test Cases N = 3 Β =30° C = 0.1 m

Test Cases N = 12 Β =10° C = 0.1 m

Parametrizing

Parameterization What properties are you exploring?

Length of blade Pitch Number of blades Wing shape

Determine the process you will step through to determine an optimized solution.

Example Determine what happens as you increase the

length of the blade. Hold the blade length constant throughout your

parametric design process. Hold the chord width and pitch constant, and

vary the number of blades. Hold the number of blades constant throughout

your parametric design process. What’s next?

Varying Chord Constant chord:

Input this value as “c = X” What if you want a different shape?

Triangular Tapered Curved Mixed

c = f(r) Determine the equation that describes the width of the chord

as a function of radial distance from the hub Remember that the value of ‘r’ varies within the loop c = 0.1*r + 0.05

If r = 0 m, c = 0.05 m If r = 0.5 m, c = 0.1 m

You may also use if, then statements!

Other Considerations

Looking forward… Remember that you will need to attach the blades

to something Dowels and a central hub will be used

Number of blades: Does using 7 blades make sense? If not, why?

Remember that we are not accounting for mass distribution: Construction is very crucial to a successful design

Blades may overlap! Think about the area that you are covering!

How will you angle your blades? Will all of the mechanical energy be converted into

electricity?

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Data You will need the raw data from your plots to

create a graphs in excel! You may use the ‘xlswrite’ function in MATLAB

It’s a good idea to keep track of your max Cp values for each design instance! You will want to plot these as a function of varying

N, c, and β. Final design comparison:

You will need to compare your final test data with your predicted MATLAB plot.

Questions?

Near Future Today:

Start parametrizing!

November 24: Detailed discussion of your report and design

setup Finish determining your final design Start building your wind turbine Start writing your report

December 1: Prepare to test your design!