|
Title:
|
|
Three-dimensional effects in stall
|
|
|
|
Author(s):
|
|
|
|
|
|
Published by:
|
Publication date:
|
|
ECN
|
1997
|
|
|
|
ECN report number:
|
Document type:
|
|
ECN-C--96-079
|
ECN publication
|
|
|
|
Number of pages:
|
Full text:
|
|
42
|
Download PDF
|
Abstract:
In a description of the 3D flow past a wind turbine rotor blade (quasi 2dboundary layer equations, retaining centrifugal and Coriolis terms) higher
order terms and radial pressure gradients were added. The corresponding
integral representation was implemented in an improved version (i.e. more
accurate near stall) of the MIT aerodynamic analysis programme XFOIL. The
resulting programme RFOIL calculates 'rotating' sectional aerodynamic
coefficients using two input parameters, a.w. the local solidity. Results
showed the typical 'rotating' triangular pressure distribution and the
associated high lift coefficients. Aerodynamic data from experimental wind
turbines however revealed that 2/3 of the local solidity gives the better
agreement. An analysis of measured power from commercial wind turbines showed
that maximum power is better predicted by using data from RFOIL. In addition,
an engineering equation which reproduces RFOIL results was created. Taken
together, the capability to predict sectional aerodynamic coefficients under
rotating conditions has improved. 23 figs., 14 refs.
Back to List