Written communications as a co-author
Coupling radiative, conductive and convective heat-transfers in a single Monte Carlo algorithm :
A general theoretical framework for linear situations
J.-M. Tregan, J.-L. Amestoy, M. Bati, J.-J. Bezian, S. Blanco, L. Brunel, C. Caliot, J. Charon, J.-F. Cornet, C. Coustet, L. d’Alençon, J. Dauchet, S. Dutour, S. Eibner, M. El Hafi, V. Eymet, O. Farges, V. Forest, R. Fournier, M. Galtier, V. Gattepaille, J. Gautrais, Z. He, F. Hourdin, L. Ibarrart, J.-L. Joly, P. Lapeyre, P. Lavieille, M.-H. Lecureux, J. Lluc, M. Miscevic, N. Mourtaday, Y. Nyffenegger, L. Pelissier, L. Penazzi, B. Piaud, C. Rodrigues-Viguier, G. Roques, M. Roger, T. Saez, G. Terre, N. Villefranque, T. Vourc’h, D. Yaacoub
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It was recently shown that radiation, conduction and convection can be combined within a single Monte Carlo algorithm and that such an algorithm immediately benefits from state-of-the-art computer-graphics advances when dealing with complex geometries. The theoretical foundations that make this coupling possible are fully exposed for the first time, supporting the intuitive pictures of continuous thermal paths that run through the different physics at work. First, the theoretical frameworks of propagators and Green’s functions are used to demonstrate that a coupled model involving different physical phenomena can be probabilized. Second, they are extended and made operational using the Feynman-Kac theory and stochastic processes. Finally, the theoretical framework is supported by a new proposal for an approximation of coupled Brownian trajectories compatible with the algorithmic design required by ray-tracing acceleration techniques in highly refined geometry.
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[Plos One 2023]
Advection, diffusion and linear transport in a single path-sampling Monte-Carlo algorithm :
Getting insensitive to geometrical refinement
L. Ibarrart, S. Blanco, C. Caliot, J. Dauchet, S. Eibner, M. El-Hafi, O. Farges, V. Forest, R. Fournier,
J. Gautrais, R. Konduru, L. Penazzi, J.-M. Tregan, T. Vourc’h, D. Yaacoub
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We address the question of numerically simulating the coupling of diffusion, advection and one-speed linear transport with the specific objective of handling increases of the amount, the geometrical refinement and the accuracy level of input data. The computer graphics research community has succeeded in designing Monte Carlo algorithms simulating linear radiation transport in physically realistic scenes with numerical costs that are insensitive to geometrical refinement: adding more details to the scene description does not affect the computation time. The corresponding benefits in terms of engineering flexibility are already fully integrated in the cinema industry and are gradually inherited by the video game industry. We show here that the same insensitivity to the complexity of the geometrical description can also be achieved when considering one-speed linear transport not only alone but coupled with diffusion and advection. Pure linear-transport paths are replaced with advection-diffusion/linear-transport paths constituted of subpaths, each representing one of the three physical phenomena in a recursive manner. Illustration is made with a porous medium involving up to 10000 pores, the computation time being strictly independent of the number of pores.
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[2023]