Shankar, PN (1975) *On the aerodynamics performance of a class vertical axis windmills.* Technical Report. National Aeronautical Laboratory, Bangalore,India.

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## Abstract

A theory is presented to estimate the aerodynamic performance of a vertical shaft wind^raill configuration13; recently developed quot;by South and Rang! (1971, 1972}* Uhe13; induced velocity is assumed to he given quot;by simple momentum13; theory arguments; a quot;blade element analysis then yields13; equations from which the mean power coefficient may quot;be calculated * If the induced velocity is assumed to quot;be -uniform the predicted power coefficients are sense what high compared to the experimental results* It is -sho^n . that the uniform induced velocity theory can 'quot;be linearised for high tip speed ratios, to yield a simple formula for the mean power coefficient, blade solidity, is the tip speed ratio based on the local x2022;wind speed and A.and A are constants determined quot;by the quot;blade o igeometry Further f -guided by the refinements earlier made to propeller1 theory an analysis incorporating noa-'uniforia iBfinced velocity over the windmill disc is presented, here calculations vhen compared with the imiform induced velocity calculations lead to a reduction in the power coefficient for tip speed ratios orresponding to the peak power coefficient and greater. Finally, when compared with the available experimental data, the calculations show encouraging agreement as regards the peak power coefficient, the effect of blade solidity ana the variation of power coefficient with13; tip speed ratio.

Item Type: | Proj.Doc/Technical Report (Technical Report) |
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Uncontrolled Keywords: | Blade element analysis;Aerodynamic performance |

Subjects: | AERONAUTICS > Aerodynamics |

Division/Department: | Aerodynamics |

Depositing User: | M/S ICAST NAL |

Date Deposited: | 15 Dec 2006 |

Last Modified: | 24 May 2010 09:50 |

URI: | http://nal-ir.nal.res.in/id/eprint/2660 |

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