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Low Speed Airfoil Design Joan Puig Project Goals ● Maximize L/D ● Easy to build ● Keep Cm at a...

Date post: 02-Jan-2016
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Low Speed Airfoil Design Joan Puig
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Page 1: Low Speed Airfoil Design Joan Puig Project Goals ● Maximize L/D ● Easy to build ● Keep Cm at a value that is not going to make the airplane unstable.

Low Speed Airfoil Design

Joan Puig

Page 2: Low Speed Airfoil Design Joan Puig Project Goals ● Maximize L/D ● Easy to build ● Keep Cm at a value that is not going to make the airplane unstable.

Project Goals

● Maximize L/D● Easy to build● Keep Cm at a value that is not going to make the

airplane unstable● Have space for a strong structure● Design an optimal airfoil for my RC airplane

Page 3: Low Speed Airfoil Design Joan Puig Project Goals ● Maximize L/D ● Easy to build ● Keep Cm at a value that is not going to make the airplane unstable.

Tools

● Panel Method to generate Cp distribution● Shape adjusting function● Optimizer● Drag estimation tools (future work...)

Page 4: Low Speed Airfoil Design Joan Puig Project Goals ● Maximize L/D ● Easy to build ● Keep Cm at a value that is not going to make the airplane unstable.

Shape Adjusting Function

● It generates any reasonable airfoil starting from a guess and a set of linerly independent bump functions.

Page 5: Low Speed Airfoil Design Joan Puig Project Goals ● Maximize L/D ● Easy to build ● Keep Cm at a value that is not going to make the airplane unstable.

Bad bump function choice

Page 6: Low Speed Airfoil Design Joan Puig Project Goals ● Maximize L/D ● Easy to build ● Keep Cm at a value that is not going to make the airplane unstable.

Optimization Process Review

● Don't assume anything about the input data● Fit the input data using a spline to the desired X

coordinate values● Pass appropriate parameters to the optimization

function● Collect data periodically

Page 7: Low Speed Airfoil Design Joan Puig Project Goals ● Maximize L/D ● Easy to build ● Keep Cm at a value that is not going to make the airplane unstable.

Guess

Page 8: Low Speed Airfoil Design Joan Puig Project Goals ● Maximize L/D ● Easy to build ● Keep Cm at a value that is not going to make the airplane unstable.

20 Iterations

Page 9: Low Speed Airfoil Design Joan Puig Project Goals ● Maximize L/D ● Easy to build ● Keep Cm at a value that is not going to make the airplane unstable.

40 Iterations

Page 10: Low Speed Airfoil Design Joan Puig Project Goals ● Maximize L/D ● Easy to build ● Keep Cm at a value that is not going to make the airplane unstable.

60 Iterations

Page 11: Low Speed Airfoil Design Joan Puig Project Goals ● Maximize L/D ● Easy to build ● Keep Cm at a value that is not going to make the airplane unstable.

Final Result

Page 12: Low Speed Airfoil Design Joan Puig Project Goals ● Maximize L/D ● Easy to build ● Keep Cm at a value that is not going to make the airplane unstable.

Convergence rate

Page 13: Low Speed Airfoil Design Joan Puig Project Goals ● Maximize L/D ● Easy to build ● Keep Cm at a value that is not going to make the airplane unstable.

Speed

● Solving a matrix is o(n^3) -> most of the time is spent here

● Try to be able to fit your matrix in the cache– 32*(n^2+8n)/(8*1024)<available cache ~128-512

● Don't calculate x^2, x^3, sin(...) exp(...^n)... every time, compute them at the beginning and use them as global variables


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