Date

2023-1-18

Author

Hassanein, Abdelrahman Hisham Ahmed Sabri

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The study investigates the effect of two inflow conditions on the wake of a model wind turbine, namely, homogenous isotropic turbulence intensity and streamwise gust. For the effect of the freestream turbulence intensity, the wake of a porous disc with a comparable thrust coefficient was used to further highlight the differences in their wakes and decay characteristics. Results show that the wake of a wind turbine model has a faster decay rate than porous discs under both freestream turbulence intensities. In addition, the wake of both models was scaled to show a collapsing self-similar wake profile. Furthermore, the decay of the maximum velocity deficit was curve fitted using a logarithmic fit where the slope of the fit was used to provide a new way to quantify the wake growth. Consequently, this could be used as a basis for a new analytical model for the far wake of wind turbines. The effects of a streamwise gust with a triangular temporal distribution on the wake of a wind turbine model were studied for three tip speed ratios. Results reveal different wake evolutions for the three cases. Furthermore, the wake profiles under gust were scaled to collapse on self-similar profiles. Moreover, the wake of the wind turbine model at a tip speed ratio of two and under triangular gust was compared to a top hat gust profile to investigate the effects of gust profiles. It was shown that the wake flow and, thus, the thrust generation mechanism of the turbine respond similarly during the rising edges of both gust profiles.

Subject Keywords

Wake, Gust, Wind turbine, Wind tunnel, active grid

URI

https://hdl.handle.net/11511/102057

Collections

Graduate School of Natural and Applied Sciences, Thesis