FAST & HydroDyn - NREL
FAST & HydroDyn - NREL
FAST & HydroDyn - NREL
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<strong>FAST</strong> Overview<br />
Linearization – Post-Processing<br />
• A MATLAB script (Eigenalysis.m) is distributed with <strong>FAST</strong>:<br />
– Reads in periodic state matrices from linearization output file<br />
– Computes 1 st order model from 2 nd , if necessary<br />
– Computes azimuth-averaged matrices<br />
– Initializes variables needed by MBC<br />
– Performs an eigenanalysis on state matrix A, resulting in<br />
frequencies/damping (eigenvalues) & mode shapes (eigenvectors)<br />
– Spreadsheet available for analyzing eigenmodes<br />
Natural Frequency<br />
(rad/sec)<br />
40<br />
30<br />
20<br />
10<br />
0<br />
Mode 2<br />
Mode 1<br />
0 1 2 3 4 5 6 7 8 9 10 11 12<br />
Rotational Speed (rad/sec)<br />
Analytical<br />
RCAS<br />
<strong>FAST</strong><br />
Flapwise Natural Frequencies Obtained From an Eigenanalysis of a Linear <strong>FAST</strong> Model<br />
National Renewable Energy Laboratory 22 Innovation for Our Energy Future
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