Received: 28 Oct 2016 – Accepted for review: 06 Nov 2016 – Discussion started: 17 Nov 2016
Abstract. In this work, large eddy simulation data is analyzed to investigate a new stochastic modeling approach for the wake of a wind turbine. The data is generated by the LES model PALM combined with an actuator disk with rotation representing the turbine. After applying a proper orthogonal decomposition (POD), three different stochastic models for the weighting coefficients of the POD modes are deduced resulting in three wake models. Their performance is investigated mainly on the basis of aeroelastic simulations of a wind turbine in the wake. Three different load cases and their statistic characteristics are compared for the original LES, truncated PODs and the stochastic wake models including different numbers of POD modes. It is shown that approximately six POD modes are enough to capture the load dynamics on large temporal scales. Modeling the weighting coefficients as independent stochastic processes leads to similar load characteristics as in the case of the truncated POD. To complete this simplified wake description, we show evidence that the small-scale dynamics can be grasped by adding to our model a homogeneous turbulent field. In this way, we present a procedure how to derive stochastic wake models from costly CFD calculations or elaborated experimental investigations. These numerically efficient models provide the added value of possible long-term studies. Depending on the aspects of interest, different minimalized models may be obtained.
How to cite. Bastine, D., Vollmer, L., Wächter, M., and Peinke, J.: Stochastic Wake Modeling Based on POD Analysis, Wind Energ. Sci. Discuss. [preprint], https://doi.org/10.5194/wes-2016-38, 2016.
Modeling of wind turbine wakes plays a key role in the maximization of the power output and lifetime of wind turbines in wind farms. In order to capture important dynamic and turbulent aspects of the wake, a new stochastic modeling approach is presented in this work. The resulting new kind of stochastic wake model captures important characteristics of loads which act on wind turbines in the wake. It might therefore be of great use for the planing and controlling of wind farms.
Modeling of wind turbine wakes plays a key role in the maximization of the power output and...