Preface

Abstract

The 23 papers in this volume constitute the proceedings of the 2021 Wake Conference. The Wake Conference series began in Visby, where it was held in 2009 and 2011. In 2013 the conference took place in Copenhagen where it was combined with the International Conference on Offshore Wind Energy and Ocean Energy. In 2015 and 2017 it went back to where it started, Visby. This year the conference will be held online due to the restrictions for Covid-19. Hosts for the conference are Professor Stefan Ivanell, Uppsala University and Professor Jens Nørkær Sørensen, Technical University of Denmark.Modern wind turbines are today clustered in large farms with a total production capacity reaching those of a nuclear power plant. When placed in a wind farm, the turbines will be fully or partially influenced by the wake of upstream turbines. This wake interaction results in a decreased power production, caused by the lower kinetic energy in the wind, and an increase in the turbulence intensity. Therefore, understanding the physical nature of vortices and their dynamics in the wake of a turbine is important for the optimal design of wind farms.The increased importance and interest in the field of wake and wind farm aerodynamics can be seen in the increased number of scientific articles on the subject. This citation growth essentially shows that the growth in the global production of electrical energy has become a scientific problem to be solved by scientists and engineers. In order to make a substantial impact on one of the most significant challenges of our time, global climate change, the wind industry’s growth must continue. A part of making this growth possible will require research into the physics of wind turbine wakes and wind farms.This conference is aimed at scientists and PhD students working in the field of wake dynamics. The conference covers the following subject areas: Wake and vortex dynamics, instabilities in trailing vortices and wakes, simulation and measurements of wakes, analytical approaches for modeling wakes, wake interaction and other wind farm investigations.We would like to thank all those that assisted in the review process for these proceedings and we are also thankful for the help we have received from the editorial team at IOP Publishing during the process.Visby, Sweden May 2021 Stefan Ivanell and Jens Nørkær Sørensen