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Title: Effects of yawed flow on wind turbine rotors

Thesis/Dissertation ·
OSTI ID:5537370

The effect of yawed flow on wind turbine rotors is examined. Results are obtained from two theoretical approaches. The first theoretical analysis involves the development and investigation of a smplified computer algorithm. The algorithm is derived from fundamental rotor equations and is used to study the effects of yawed flow on steady-state, average rotor performance. The second theoretical analysis is dynamic simulation of a rotor in yawed flow. The analysis is based on blade element theory and dynamic inflow theory, and neglects stall effects. The analysis is designed to calculate local aerodynamic forces and moments blade angle-of-attack profiles, induced flow profiles, and teeter or passive cyclic pitch deflections for rotors with a teetering axis or with cyclic pitch. A state-variable approach is used with a predictor-corrector solution to the system of first-order differential equations in order to obtain a time-history solution. Applications of the dynamic simulation model are used to investigate operating limits due to stall, gust response, and passive cyclic pitch response. Correlations are presented with the simplified theory and with experimental results, where applicable. Experimental results are presented from wind tunnel tests in which a model rotor was operated in yawed flow. The results are compared with other wind tunnel test results and with some theoretical results. Experimental results are also peresented from atmospheric tests of a 7.6 meter (25 ft) diameter, two-bladed, yaw-controlled wind turbine with passive cyclic pitch. Comparisons between the theoretical approaches and the experimental data show that both computer models are useful in analyzing the effects of yawed flow on wind turbine rotor performance.

OSTI ID:
5537370
Resource Relation:
Other Information: Thesis (Ph. D.)
Country of Publication:
United States
Language:
English