Public thesis defense Jean-Baptiste CRISMER - IMMC
sst |
Large Eddy Simulations of controlled Airborne Wind Energy Systems flying in turbulent flows
Thursday August 27th, 2026 - 4:15pm - Auditorium BARB93 - Place Sainte-Barbe, 1 - 1348 Louvain-la-Neuve
Wind energy is expected to play a central role in the energy transition to carbon-neutral energy system, with installed capacity projected to increase substantially in the coming decades. To this end, the size of horizontal-axis wind turbines is continuously increasing, which raises structural challenges and requires increasing material resources. Those challenges have triggered interest in alternative technologies. Airborne wind energy systems (AWES) show great potential and has recently gained a great deal of interest. However, AWESs development is still at an early stage, and their ability to operate reliably under turbulent wind conditions and within wind farms requires further investigation. This thesis presents a computational framework based on large eddy simulation (LES) to study AWES operating in ambient turbulence and in waked conditions representative of wind farms. Within the LES flow solver, the kites are represented using a model based on an actuator line for the main wing with its ailerons, and complemented with models for the tail control surfaces (rudder and elevator). The flow solver is coupled, via a two-way coupling, to a control module based on model-predictive control (MPC), to track optimal trajectories. The first part of the thesis investigates the wakes generated by curved- and straight-wing AWES, representative of soft- and rigid-wing concepts, and demonstrates that the wake structure depends on the kite geometry. The subsequent chapters focus on straight rigid-wing kites. The robustness of the MPC controller is then evaluated under turbulent inflow conditions, showing its ability to maintain accurate trajectory tracking despite atmospheric turbulence. The framework is subsequently applied to more complex operating scenarios. When flying within the wake of another kite, the controller successfully tracks the prescribed trajectory. Depending on the spacing and synchronization between the two systems, the downstream kite either avoids the wake and experiences negligible wake effects or flies within it, resulting in power losses of up to 6%. Finally, the kite is simulated within a realistic atmospheric boundary layer and in the wake of a wind turbine. Even when traversing the wind turbine wake, the controller maintains trajectory tracking, although with reduced accuracy and power losses of approximately 5–10%. Overall, these results quantify the performance of AWES under realistic farm-like operating conditions, demonstrate both the robustness and the limitations of the proposed control strategy, and show that wake interactions can significantly affect power production and trajectory-tracking performance while also highlighting opportunities for wake mitigation.
Jury members
Prof. Grégoire Winckelmans (UCLouvain), Supervisor
Prof. Aude Simar (UCLouvain), Chairperson
Prof. Francesco Contino (UCLouvain), Secretary
Prof. Denis-Gabriel Caprace (UCLouvain)
Dr. Joris Degroote (UGent)
Dr. Filippo Trevisi (Politecnico di Milano)