optimisation de processus aéronautiques et biomédicaux
Publications scientifiques au M2P2
2024
Tom Fringand, Loic Mace, Isabelle Cheylan, Marien Lenoir, Julien Favier. Analysis of Fluid–Structure Interaction Mechanisms for a Native Aortic Valve, Patient-Specific Ozaki Procedure, and a Bioprosthetic Valve. Annals of Biomedical Engineering, 2024, 52 (11), pp.3021-3036. ⟨10.1007/s10439-024-03566-1⟩. ⟨hal-04928780⟩ Plus de détails...
The Ozaki procedure is a surgical technique which avoids to implant foreign aortic valve prostheses in human heart, using the patient’s own pericardium. Although this approach has well-identified benefits, it is still a topic of debate in the cardiac surgical community, which prevents its larger use to treat valve pathologies. This is linked to the actual lack of knowledge regarding the dynamics of tissue deformations and surrounding blood flow for this autograft pericardial valve. So far, there is no numerical study examining the coupling between the blood flow characteristics and the Ozaki leaflets dynamics. To fill this gap, we propose here a comprehensive comparison of various performance criteria between a healthy native valve, its pericardium-based counterpart, and a bioprosthetic solution, this is done using a three-dimensional fluid–structure interaction solver. Our findings reveal similar physiological dynamics between the valves but with the emergence of fluttering for the Ozaki leaflets and higher velocity and wall shear stress for the bioprosthetic heart valve.
Tom Fringand, Loic Mace, Isabelle Cheylan, Marien Lenoir, Julien Favier. Analysis of Fluid–Structure Interaction Mechanisms for a Native Aortic Valve, Patient-Specific Ozaki Procedure, and a Bioprosthetic Valve. Annals of Biomedical Engineering, 2024, 52 (11), pp.3021-3036. ⟨10.1007/s10439-024-03566-1⟩. ⟨hal-04928780⟩
Loïc Georges Macé, Tom Fringand, Isabelle Cheylan, Laurent Sabatier, Laurent Meille, et al.. Three-dimensional modelling of aortic leaflet coaptation and load-bearing surfaces: in silico design of aortic valve neocuspidizations. Interdisciplinary Cardiovascular and Thoracic Surgery, 2024, 39 (1), ⟨10.1093/icvts/ivae108⟩. ⟨hal-04971088⟩ Plus de détails...
Three-dimensional (3D) modelling of aortic leaflets remains difficult due to insufficient resolution of medical imaging. We aimed to model the coaptation and load-bearing surfaces of the aortic leaflets and adapt this workflow to aid in the design of aortic valve neocuspidizations. METHODS Geometric morphometrics, using landmarks and semilandmarks, was applied to the geometric determinants of the aortic leaflets from computed tomography, followed by an isogeometric analysis using Non-Uniform Rational Basis Splines (NURBS). Ten aortic valve models were generated, measuring determinants of leaflet geometry defined as 3D NURBS curves, and leaflet coaptation and load-bearing surfaces were defined as 3D NURBS surfaces. Neocuspidizations were obtained by either shifting the upper central coaptation landmark towards the sinotubular junction or using parametric neo-landmarks placed on a centreline drawn between the centroid of the aortic root base and centroid of a circle circumscribing the 3 upper commissural landmarks. RESULTS The ratio of the leaflet free margin length to the geometric height was 1.83, whereas the ratio of the commissural coaptation height to the central coaptation height was 1.93. The median coaptation surface was 137 mm2 (IQR 58) and the median load-bearing surface was 203 mm2 (60) per leaflet. Neocuspidization multiplied the central coaptation height by 3.7 and the coaptation surfaces by 1.97 and 1.92 using the native coaptation axis and centroid coaptation axis, respectively. CONCLUSIONS Geometric morphometrics reliably defined the coaptation and load-bearing surfaces of aortic leaflets, enabling an experimental 3D design for the in silico neocuspidization of aortic valves.
Loïc Georges Macé, Tom Fringand, Isabelle Cheylan, Laurent Sabatier, Laurent Meille, et al.. Three-dimensional modelling of aortic leaflet coaptation and load-bearing surfaces: in silico design of aortic valve neocuspidizations. Interdisciplinary Cardiovascular and Thoracic Surgery, 2024, 39 (1), ⟨10.1093/icvts/ivae108⟩. ⟨hal-04971088⟩
Journal: Interdisciplinary Cardiovascular and Thoracic Surgery
Tom Fringand, Isabelle Cheylan, Marien Lenoir, Loic Mace, Julien Favier. A stable and explicit fluid–structure interaction solver based on lattice-Boltzmann and immersed boundary methods. Computer Methods in Applied Mechanics and Engineering, 2024, 421, pp.116777. ⟨10.1016/j.cma.2024.116777⟩. ⟨hal-04971126⟩ Plus de détails...
Fluid-structure interaction (FSI) occurs in a wide range of contexts, from aeronautics to biological systems. To numerically address this challenging type of problem, various methods have been proposed, particularly using implicit coupling when the fluid and the solid have the same density, i.e., the density ratio is equal to 1. Aiming for a computationally efficient approach capable of handling strongly coupled dynamics and/or realistic conditions, we present an alternative to the implicit formulation by employing a fully explicit algorithm. The Lattice Boltzmann Method (LBM) is used for the fluid, with the finite element method (FEM) utilized for the structure. The Immersed Boundary Method (IBM) is applied to simulate moving and deforming boundaries immersed in fluid flows. The novelty of this work lies in the combination of Laplacian smoothing at the fluid/solid interface, an improved collision model for the LBM, and a reduction of non-physical frequencies on the structure mesh. The use of these adaptations results in a solver with remarkable stability properties, a primary concern when dealing with explicit coupling. We validate the numerical framework on several challenging test cases of increasing complexity, including 2D and 3D configurations, density ratio of 1, and turbulent conditions.
Tom Fringand, Isabelle Cheylan, Marien Lenoir, Loic Mace, Julien Favier. A stable and explicit fluid–structure interaction solver based on lattice-Boltzmann and immersed boundary methods. Computer Methods in Applied Mechanics and Engineering, 2024, 421, pp.116777. ⟨10.1016/j.cma.2024.116777⟩. ⟨hal-04971126⟩
Journal: Computer Methods in Applied Mechanics and Engineering
Isabelle Cheylan, Tom Fringand, Jérôme Jacob, Julien Favier. Analysis of the immersed boundary method for turbulent fluid-structure interaction with Lattice Boltzmann method. Journal of Computational Physics, 2023, 492, pp.112418. ⟨10.1016/j.jcp.2023.112418⟩. ⟨hal-04543923⟩ Plus de détails...
Isabelle Cheylan, Julien Favier, Pierre Sagaut. Immersed boundary conditions for moving objects in turbulent flows with the lattice-Boltzmann method. Physics of Fluids, 2021, 33 (9), pp.095101. ⟨10.1063/5.0062575⟩. ⟨hal-03597108⟩ Plus de détails...
An immersed boundary method is coupled to a turbulent wall model and Large Eddy Simulation, within the Lattice-Boltzmann framework. The method is able to handle arbitrarily moving objects immersed in a high Reynolds number flow and to accurately capture the shear layer and near wall effects. We perform a thorough numerical study which validates the numerical method on a set of test-cases of increasing complexity, in order to demonstrate the application of this method to industrial conditions. The robustness and accuracy of the method are assessed first in a static laminar configuration, then in a mobile laminar case, and finally in a static and oscillating turbulent simulation. In all cases, the proposed method shows good results compared to the available data in the literature.
Isabelle Cheylan, Julien Favier, Pierre Sagaut. Immersed boundary conditions for moving objects in turbulent flows with the lattice-Boltzmann method. Physics of Fluids, 2021, 33 (9), pp.095101. ⟨10.1063/5.0062575⟩. ⟨hal-03597108⟩
Isabelle Cheylan, Julien Favier, Pierre Sagaut. Immersed boundary conditions for moving objects in turbulent flows with the lattice-Boltzmann method. Physics of Fluids, 2021, 33 (9), pp.095101. ⟨10.1063/5.0062575⟩. ⟨hal-03514710⟩ Plus de détails...
An immersed boundary method is coupled to a turbulent wall model and Large Eddy Simulation, within the Lattice-Boltzmann framework. The method is able to handle arbitrarily moving objects immersed in a high Reynolds number flow and to accurately capture the shear layer and near wall effects. We perform a thorough numerical study which validates the numerical method on a set of test-cases of increasing complexity, in order to demonstrate the application of this method to industrial conditions. The robustness and accuracy of the method are assessed first in a static laminar configuration, then in a mobile laminar case, and finally in a static and oscillating turbulent simulation. In all cases, the proposed method shows good results compared to the available data in the literature.
Isabelle Cheylan, Julien Favier, Pierre Sagaut. Immersed boundary conditions for moving objects in turbulent flows with the lattice-Boltzmann method. Physics of Fluids, 2021, 33 (9), pp.095101. ⟨10.1063/5.0062575⟩. ⟨hal-03514710⟩
Isabelle Cheylan, Song Zhao, Pierre Boivin, Pierre Sagaut. Compressible pressure-based Lattice-Boltzmann applied to humid air with phase change. Applied Thermal Engineering, 2021, pp.116868. ⟨10.1016/j.applthermaleng.2021.116868⟩. ⟨hal-03180596⟩ Plus de détails...
A new compressible pressure-based Lattice Boltzmann Method is proposed to simulate humid air flows with phase change. The variable density and compressible effects are fully resolved, effectively lifting the Boussinesq approximation commonly used, e.g. for meteorological flows. Previous studies indicate that the Boussinesq assumption can lead to errors up to 25%, but the model remains common, for compressible models often suffer from a lack of stability. In order to overcome this issue, a new pressure-based solver is proposed, exhibiting excellent stability properties. Mass and momentum conservation equations are solved by a hybrid recursive regularized Lattice-Boltzmann approach, whereas the enthalpy and species conservation equations are solved using a finite volume method. The solver is based on a pressure-based method coupled with a predictor-corrector algorithm, and incorporates a humid equation of state, as well as a specific boundary condition treatment for phase change. In particular, boundary conditions that handle mass leakage are also proposed and validated. Three test cases are investigated in order to validate this new approach: the Rayleigh-Bénard instability applied to humid air, the atmospheric rising of a condensing moist bubble, and finally the evaporation of a thin liquid film in a vertical channel. Results indicate that the proposed pressure-based Lattice-Boltzmann model is stable and accurate on all cases.
Isabelle Cheylan, Song Zhao, Pierre Boivin, Pierre Sagaut. Compressible pressure-based Lattice-Boltzmann applied to humid air with phase change. Applied Thermal Engineering, 2021, pp.116868. ⟨10.1016/j.applthermaleng.2021.116868⟩. ⟨hal-03180596⟩
Isabelle Cheylan, Guillaume Fritz, Denis Ricot, Pierre Sagaut. Shape Optimization Using the Adjoint Lattice Boltzmann Method for Aerodynamic Applications. AIAA Journal, 2019, 57 (7), pp.2758-2773. ⟨10.2514/1.J057955⟩. ⟨hal-02468051⟩ Plus de détails...
The present work focuses on shape optimization using the lattice Boltzmann method applied to aerodynamic cases. The adjoint method is used to calculate the sensitivities of the drag force with respect to the shape of an object. The main advantage of the adjoint method is its cost, because it is independent from the number of optimization parameters. The approach used consists in developing a continuous adjoint of the primal problem discretized in space, time, and velocities. An adjoint lattice Boltzmann equation is thus found, which is solved using the same algorithms as in the primal problem. The test cases investigate new features compared to what exists in the literature, such as the derivation of the grid refinement models in the primal problem to obtain their adjoint counterparts, but also the derivation of a double-relaxation-time algorithm and the Ginzburg et al. interpolation at the wall ("Two-Relaxation-Time Lattice Boltzmann Scheme: About Parametrization, Velocity, Pressure and Mixed Boundary Conditions," Communications in Computational Physics, Vol. 3, No. 2, 2008, pp. 427-478). Regarding the unsteadiness of the primal problem, two methods differing in accuracy and computational effort are compared using a two-dimensional unsteady case. Finally, this first-of-a-kind adjoint solver is applied to a large-scale threedimensional turbulent case (the flow of air around a car at a speed of 130 km/h), which shows its usefulness in the industry.
Isabelle Cheylan, Guillaume Fritz, Denis Ricot, Pierre Sagaut. Shape Optimization Using the Adjoint Lattice Boltzmann Method for Aerodynamic Applications. AIAA Journal, 2019, 57 (7), pp.2758-2773. ⟨10.2514/1.J057955⟩. ⟨hal-02468051⟩
