1. Troubleshooting, Parametrization, and Design Professor Christiani 11/17/2014

2. Goals  Troubleshooting:  Ensure your code is running properly  Parametrizing:  Develop a strategy for optimization  Other considerations:  Design setup  Report

4. What should the output look like? Small pitch angle

5. What should the output look like? Large pitch angle

6. 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!

7. Test Cases  N = 3  Β = 30°  C = 0.1 m

8. Test Cases  N = 12  Β = 10°  C = 0.1 m

10. 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.

11. 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?

12. 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!

14. 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?

15. Corners past 1m envelope Ground Clearance Stand Clearance Not AcceptableAcceptable Wind Tunnel Test Stand Decrease Θ or W Wind Tunnel Test Stand Θ W

16. 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.

17. Questions?

18. 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!