Contrôle des vibrations induites par vortex dans le sillage d'un cylindre monté sur ressorts (thèse: 2014 - 2017)
Publications scientifiques au M2P2
2025
Iko Midani, Valentin Ledermann, Eddy Constant, Martin Spel, Laurent Stainier, et al.. Immersed boundary formulation for complex geometries in hypersonic flows: Application to atmospheric reentry. Computers and Fluids, 2025, 299, ⟨10.1016/j.compfluid.2025.106715⟩. ⟨hal-05468238⟩ Plus de détails...
This article discusses the challenges of modeling atmospheric reentry using computational fluid dynamics (CFD) due to its complexity and practical industrial applications. Ablation phenomena caused by high energy make it difficult and time-consuming to use a ''high-fidelity'' CFD method to accurately measure forces and heat flux. As a result, methods based on Newton's theory are used to model aerodynamic forces, incorporating statistical correlations from CFD results to estimate heat fluxes. However, these methods sacrifice accuracy for CPU and engineering time and have difficulty representing realistic physics when complex phenomena occur, such as shock interactions. To bridge the gap between approximate and high-fidelity methods, we propose a new approach using an automatic grid generation method of the octree Cartesian type coupled to a solver solving Euler's equations. To apply the boundary condition accurately we compared two immersed boundary methods: a diffuse interface method and a sharp interface method under hypersonic flow configurations. We present a comparative study of these two formulations on verification and validation phases, including an academic test case and an industrial case on a real reentry spacecraft. The novelty lies in applying these methods to complex cases involving strong discontinuities (attached shocks). After concluding this comparative study, we demonstrate that with adapted formulations and an optimized approach, IB methods can handle complex geometries typical of atmospheric reentry.
Iko Midani, Valentin Ledermann, Eddy Constant, Martin Spel, Laurent Stainier, et al.. Immersed boundary formulation for complex geometries in hypersonic flows: Application to atmospheric reentry. Computers and Fluids, 2025, 299, ⟨10.1016/j.compfluid.2025.106715⟩. ⟨hal-05468238⟩
Eddy Constant, Julien Favier, Marcello Meldi, Philippe Meliga, Eric Serre. An immersed boundary method in OpenFOAM : Verification and validation. Computers and Fluids, 2017, 157, pp.55 - 72. ⟨10.1016/j.compfluid.2017.08.001⟩. ⟨hal-01591562⟩ Plus de détails...
The present work proposes a modified Pressure-Implicit Split-Operator (PISO) solver integrating the recent Immersed Boundary Method (IBM) proposed by Pinelli et al. [1] in order to perform reliable simulations of incompressible flows around bluff bodies using the open source toolbox OpenFOAM version 2.2 (ESI-OpenCFD [2]). The (IBM) allows for a precise representation of fixed and moving solid obstacles embedded in the physical domain, using uniform or stretched Cartesian meshes. Owing to this feature, the maximum level of accuracy and scalability of the numerical solvers can be systematically achieved. An iterative scheme based on sub-iterations between (IBM) and pressure correction has been implemented in the native (PISO) solver of OpenFOAM. This allows one to use fast optimized Poisson solvers while satisfying simultaneously the divergence-free flow state and the no-slip condition at the body surface. To compute the divergence of the momentum equation (in the PISO loop) and the interpolation of the fluxes, we propose an hybrid calculation with an analytical resolution (using the kernel function equation) of the quantities involving the force term (singular quantities). A careful and original verification study has been carried out which allows to estimate three different errors related to the discretization and to the (IBM). Various 2D and 3D well-documented test cases of academic flows around fixed or moving cylinders have been simulated and carefully validated against existing data from the literature in a large range of Reynolds numbers, Re = 30 − 3900 and in the frame of DNS and DDES OpenFOAM native models.
Eddy Constant, Julien Favier, Marcello Meldi, Philippe Meliga, Eric Serre. An immersed boundary method in OpenFOAM : Verification and validation. Computers and Fluids, 2017, 157, pp.55 - 72. ⟨10.1016/j.compfluid.2017.08.001⟩. ⟨hal-01591562⟩
