A non-symmetric Gaussian wake model for lateral wake-to-wake interactions

Abstract

In this paper, we propose a new non-symmetric Gaussian wake model, which allows for different lateral expansions on the two sides of a wake to account for its interaction with neighbouring wakes. The proposed model is formulated following classical speed-deficit assumptions and momentum conservation. Departing from the existing literature, a non-symmetric Gaussian function is used to represent the velocity deficit in the wake. Accordingly, different wake expansions are assumed on the two sides of the wake, each expressed as a function of the locally prevailing turbulence intensity. The model considers that wake-added turbulence changes with downstream distance; hence, the turbulence intensity on a wake-immersed side of the wake is location dependent. The new model is compared to LES-ALM numerical simulations of three turbines in partial wake overlap. The free parameters of the model describing the wake development are tuned based on the CFD results. Results indicate that the new model provides for a very good agreement of the velocity profiles at different downstream positions, generating an improved representation of merging wakes and their downstream development.

A New Study on the Effect of the Partial Wake Generated in a Wind Farm

“…In various environmental conditions, they indicated that yaw effects can induce significant load variation, which is detrimental to structural stability. In another aspect of the research, Vad et al [33] proposed a new model of a non-symmetric Gaussian wake, where the wake affecting the actuator disk of a leading turbine does not exhibit uniformity, thus leading to partial wake overlap. This model uses a non-symmetric Gaussian function to represent the velocity deficit in the wake, resulting in different forms of wake expansion and, consequently, the formation of a partial wake.…”