Grégoire Winckelmans
Recent publications

obtained a mechanical engineer degree from UCLouvain (1983), a postgraduate degree in aeronautics and aerospace from the von Karman Institute (VKI, 1984), a M.S. degree (1985) and a Ph.D. degree (1989) in aeronautics from the California Institute of Technology (Caltech). He was senior scientist at STD Research Corp. until 1992, then postdoc at Caltech until 1993, then assistant professor at U. of Sherbrooke. He joined UCLouvain in 1996 and is full professor since 2007. His service duties include: member of the “Conseil d’Administration” of Cenaero (since 2003), of Skywin aerospace cluster of Wallonia (since 2006), president of the mechanical engineering dept. (2007-2009), then of iMMC (2009 -2015).

His research interests cover fluid mechanics, and more specifically turbulent flows, together with their numerical simulation (DNS, LES) deployed in HPC, and their modelling; advanced numerical methods (eulerian, lagrangian, hybrid vortex particle-mesh (VPM) method) and subgrid-scale modelling (also multi-scale); vortical and turbulent flows: wakes of aircraft, wind turbines, rotorcraft.

He and the research group worked on many projects devoted to aircraft wake vortices since 1994: Canadian project (VFS), EC projects (I-WAKE, ATC-WAKE, AWIATOR, WakeNet2-Europe, FAR-WAKE, FLYSAFE, CREDOS, WakeNet3-Europe, GREEN-Wake, UFO), RW project (LASEF), research contracts in projects (TBS, WIDAO, SESAR 6.8.1 for Eurocontrol, SESAR 12.2.2 for Thales, SESAR 9.11 and 9.30 for Airbus), service contracts (Airbus). They also developed the WAKE4D software for operational modelling of aircraft wake vortices, and developed metrics for the assessment of wake hazard (also for RECAT-EU and for RECAT2-EU). He his co-founder, with Prof. Philippe Chatelain and Dr. Ivan De Visscher, of Wake Prediction Technologies (WaPT): a UCLouvain spin-off created in 2013; also built on the expertise developed in the simulation and modelling of aircraft wakes and wind turbine wakes (since 2010).

Research collaborations include Caltech, Stanford (CTR), Cenaero, UMons and DTU.

Research group(s): TFL

PhD and Post-doc researchers under my supervision:

Implementation of an incompressible hybrid Eulerian-Lagrangian external flow solver
Philippe Billuart

Philippe Billuart is working on the development of a new numerical solver that will be able to solve accurately and efficiently any low Mach number external flows. His research is focusing on the hybrid Eulerian-Lagrangian solvers for the incompressible Navier-Stokes equations. Those approaches are based on the decomposition of the computational domain : an Eulerian grid-based solver is used for the computation of the near-wall region, while a Lagrangian vortex method solves the wake region. Even though the coupling of particle methods with Eulerian solvers is not new, only 3D weak coupling were developed so far. This thesis aims to develop a 3D strong coupling ; i.e. a coupling where the Schwarz iterations are not longer required to ensure consistent boundary conditions on each subdomain. As the Schwarz algorithm becomes expensive in 3D, the computational gain in the developed approach should be very significant.

Denis-Gabriel Caprace

This research is about developing tools for wake flow analysis, and their application to rotorcraft and aircraft in formation flight.

Wall modelling in Large-Eddy Simulations, with application to supersonic ejectors
Romain Debroeyer

The goal of this research is to perform high fidelity Large-Eddy Simulations (LES) of supersonic ejectors. These simulations will give a better understanding of the unsteady phenomena occurring in the ejector and how it transitions from on to off-design operation. Wall models for those LES simulations will be implemented so as to decrease the number of grid points required and hence decrease the simulation time.

FSI for wind turbines
François Trigaux

Wind energy is one of the most promising renewable energy to ensure the transition towards a sustainable energy mix. At the national level, the offshore installed power will reach 3 GW in 2020 and hence become the most important source of low carbon energy. However, with wind turbines now reaching a diameter of up to 160m, there is a need to consider structural effects into the design, as the large deformation and unsteady loads can modify the aerodynamics or lead to vibration instability. Numerical simulations are an efficient and flexible tool to answer this need.
Our goal is to further advance the state-of-the-art of the simulation of both horizontal and vertical axis wind turbines by handling correctly the fluid structure interaction. The first part of project consists in the efficient coupling of the fluid and the flow solver. The wind turbine deformation will be computed using a detailed FEM solver developed at UGent, whereas the flow will be computed using a scale-resolving tool based on large-edddy simulation and HPC. The effect on the flow of the turbine will be handled with an actuator lines method. Using LES for the flow solver is a novel approach, that will capture the unsteadiness of the flow at a much higher level than the currently used URANS. This will allow to study the unsteady loads acting on the turbine, its vibration modes and the effect of deformation on the power and the wake.
The developed tool will then be used to study load alleviation methods such as working on the tip speed ratio, the orientation, and performing individual pitch control. The FSI in complex situation will also be performed, such as wind turbines interacting with the wake of preceeding ones. The evolution of the loads when the turbines are subject to gusts will also be characterized, including the study of the artificial gust generation. The aeroelasticity of WTs in a floating configuration will also be investigated.

Simulations of Airborne Wind Energy Systems using simple models and Large Eddy Simulations
Jean-Baptiste Crismer

In Belgium, the last offshore sites likely to host wind farms are being exploited. It arises the question: How to increase the power production of existing wind farms? The idea is thus to investigate the feasibility of adding airborne wind energy systems (AWES) on top of exiting wind farms to increase their energy production. As no simulation tools allow to take into account complex control, unsteady aerodynamics, turbulent inflow and aeroelastic behaviour for AWES. The BORNE (Belgian Offshore aiRborne wind Energy) project, in collaboration with UGent, will firstly intend to close this gap, to then provide insight with simulations of different scenarios. The contributions of UCLouvain focuses on the accurate modelling of the aerodynamics of AWES wings (rigid or kites) to provide accurate large eddy simulations. We will first go through the aerodynamic characterisation of such wings. To then provide a simple model based on the Prandtl lifting line theory. Then we will calibrate a semi-empirical dynamic stall model to consider more accurately the unsteady behaviour. Improvements will be made on the actual actuator line model to best represent AWES, considering aerodynamics and aeroelasticity. Then the behaviour of AWES in atmospheric boundary layer, turbulent wind and the interaction with wind turbines wakes will be studied.

Youri Marchal