Towards physics-based operational modeling of the unsteady wind turbine response to atmospheric and wake-induced turbulence

The objective of the present work is to develop a tool able to predict, in a computationally affordable way, the unsteady wind turbine power production and loads as well as its wake dynamics, as a function of the turbine dynamics and incoming wind conditions. Based on the lessons learned from a previous study about the characterization of the unsteady wake dynamics, the framework for an operational wake model is presented. The approach relies on an underlying vorticity-based skeleton consisting of different components, such as a regularized Vortex Sheet Tube (VST) and Vortex Dipole Line (VDL). Physically based evolution equations, accounting for the various flow phenomena occurring in the wake (such as advection, turbulent diffusion/core spreading, source/sink terms, etc.), are then derived. Once calibrated, the wake model is shown to be in good agreement with results of high-fidelity Large Eddy Simulations (LES) obtained using an Immersed Lifting Line-enabled Vortex Particle-Mesh method.