Journal article
Far-wake meandering induced by atmospheric eddies in flow past a wind turbine
A novel algorithm is developed to calculate the nonlinear optimal boundary perturbations in three-dimensional incompressible flow. An optimal step length in the optimization loop is calculated without any additional calls to the Navier-Stokes equations. The algorithm is applied to compute the optimal inflow eddies for the flow around a wind turbine to clarify the mechanisms behind wake meandering, a phenomenon usually observed in wind farms.
The turbine is modelled as an actuator disc using an immersed boundary method with the loading prescribed as a body force. At Reynolds number (based on free-stream velocity and turbine radius) Re = 1000, the most energetic inflow perturbation has a frequency omega = 0.8-2, and is in the form of an azimuthal wave with wavenumber m = 1 and the same radius as the actuator disc.
The inflow perturbation is amplified by the strong shear downstream of the edge of the disc and then tilts the rolling-up vortex rings to induce wake meandering. This mechanism is verified by studying randomly perturbed flow at Re
Language: | English |
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Year: | 2018 |
Pages: | 190-209 |
ISSN: | 14697645 and 00221120 |
Types: | Journal article |
DOI: | 10.1017/jfm.2018.275 |
ORCIDs: | Sorensen, J. N. and 0000-0002-8452-5773 |