29 June 2023
16:15
Louvain-la-Neuve
Place Sainte Barbe, auditorium BARB94
External flow simulations are ubiquitous in several scientific and engineering fields, with e.g. biolocomotion, vehicle aero- or hydrodynamics, wind energy, … The associated flow configurations are quite challenging as they usually require the accurate capture of (1) the near-wall region in order to accurately measure the forces on the device surface, and also of (2) the wake when interacting with a downstream device.
Academia and industry have thus far proposed two numerical solutions to tackle such flows.
A first one consists in vorticity-based Lagrangian methods, or vortex methods in short. Such techniques enjoy some computational benefits that are particularly interesting for the resolution of the wake regions. However, vortex methods are ill-suited to capture high Reynolds number boundary layers because of their intrinsic isotropic computational elements. A second group of methods gathers Eulerian body-fitted grid solvers, such as finite differences, finite volumes, finite elements, etc. They allow the use of anisotropic computational elements that conform to the body and are ideally suited to capture the boundary layers; their Eulerian handling of advection however causes them to fall behind in the capture of the wake because of the involved dispersion and diffusion errors.
This naturally leads to the proposition of combining the complementary advantages of Lagrangian vortex methods and body fitted-grid solvers in a coupled approach.
This thesis proposes a novel weak coupling to perform this in a computationally efficient manner. In particular, it improves upon pre-existing efforts that often led to noisy, and thence not exploitable, aerodynamic efforts and lacked robustness in the conservation of circulation.
This new coupling methodology has been developed and implemented for two types of body-fitted solvers: finite volumes and finite differences. Its performance is v
erified on the benchmark problem of the flow past a cylinder, both in an impulsive start and in a shedding regime.
Jury members :
Prof. Grégoire Winckelmans (UCLouvain, Belgium), supervisor
Prof. Philippe Chatelain (UCLouvain, Belgium), supervisor
Prof. Renaud Ronsse (UCLouvain, Belgium), chairperson
Prof. Laurent Bricteux (Umons, Belgium)
Dr. Matthieu Duponcheel (UCLouvain, Belgium)
Prof. Pierre Bénard (INSA Rouen Normandie, France)
Prof. Carlos Simão Ferreira (TUDelft, Pays-Bas)