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Related papers: Ray Effect in Rarefied Flow Simulation

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Discrete flow mapping was recently introduced as an efficient ray based method determining wave energy distributions in complex built up structures. Wave energy densities are transported along ray trajectories through polygonal mesh…

Computational Physics · Physics 2016-12-21 Janis Bajars , David Chappell , Niels Sondergaard , Gregor Tanner

In recent years, Rectified flow (RF) has gained considerable popularity largely due to its generation efficiency and state-of-the-art performance. In this paper, we investigate the degree to which RF automatically adapts to the intrinsic…

Machine Learning · Statistics 2026-02-24 Saptarshi Roy , Alessandro Rinaldo , Purnamrita Sarkar

We study the numerical behaviour of a particle method for gradient flows involving linear and nonlinear diffusion. This method relies on the discretisation of the energy via non-overlapping balls centred at the particles. The resulting…

Analysis of PDEs · Mathematics 2016-12-07 J. A. Carrillo , Y. Huang , F. S. Patacchini , G. Wolansky

Accurate and efficient prediction of multi-scale flows remains a formidable challenge. Constructing theoretical models and numerical methods often involves the design and optimization of parameters. While gradient descent methods have been…

Computational Physics · Physics 2026-02-10 Tianbai Xiao

Small random perturbations may have a dramatic impact on the long time evolution of dynamical systems, and large deviation theory is often the right theoretical framework to understand these effects. At the core of the theory lies the…

Numerical Analysis · Mathematics 2017-10-11 Tobias Grafke , Tobias Schaefer , Eric Vanden-Eijnden

Trajectories of a buoyant spherical solid particle in a linear shear flow were investigated at low Reynolds numbers. A two-dimensional CFD analysis was performed to simulate the solid-fluid flows. Our numerical model, the discrete phase…

Fluid Dynamics · Physics 2019-02-14 Nima Fathi , Seyed Sobhan Aleyasin , Peter Vorobieff , Goodarz Ahmadi

Building upon recent developments of force-based estimators with a reduced variance for the computation of densities, radial distribution functions or local transport properties from molecular simulations, we show that the variance can be…

Chemical Physics · Physics 2021-05-18 Samuel W. Coles , Etienne Mangaud , Daan Frenkel , Benjamin Rotenberg

Expressions for local discrete variance decay (DVD) rates are directly derived from discrete tracer equations without any assumptions on discrete fluxes of the second moment. Spurious mixing (SM) associated with numerical implementations of…

Atmospheric and Oceanic Physics · Physics 2026-03-26 Tridib Banerjee , Sergey Danilov , Knut Klingbeil

Simulating complex gas flows from turbulent to rarefied regimes is a long-standing challenge, since turbulence and rarefied flow represent contrasting extremes of computational aerodynamics. We propose a multiscale method to bridge this…

Fluid Dynamics · Physics 2024-08-16 Songyan Tian , Lei Wu

Automated Vehicle (AV) validation based on simulated testing requires unbiased evaluation and high efficiency. One effective solution is to increase the exposure to risky rare events while reweighting the probability measure. However,…

Machine Learning · Computer Science 2024-09-25 Yichun Ye , He Zhang , Ye Tian , Jian Sun , Karl Meinke

Relativistic jets associated with long/soft gamma-ray bursts are formed and initially propagate in the interior of the progenitor star. Because of the subsequent loss of their external pressure support after they cross the stellar surface,…

High Energy Astrophysical Phenomena · Physics 2014-07-21 Konstantinos Sapountzis , Nektarios Vlahakis

Monitoring time-dependence with diffusion MRI yields observables sensitive to compartment sizes (restricted diffusion) and membrane permeability (water exchange). However, restricted diffusion and exchange have opposite effects on the…

Experimental analysis of cavitation bubble dynamics typically uses optical imaging. However, images are often severely affected by distortions and shadows due to refraction and total reflection at the liquid--gas interface. Here it is shown…

We outline a methodology for the simulation of particle-laden flows whereby the dispersed and fluid phases are two-way coupled. The drag force which couples fluid and particle momentum depends on the undisturbed fluid velocity at the…

Fluid Dynamics · Physics 2020-04-21 J. A. K. Horwitz , G. Iaccarino , J. K. Eaton , A. Mani

For accurate simulations of rarefied gas flows around moving obstacles, we propose a cut cell method on Cartesian grids: it allows exact conservation and accurate treatment of boundary conditions. Our approach is designed to treat Cartesian…

Numerical Analysis · Mathematics 2016-04-20 Guillaume Dechristé , Luc Mieussens

The randomization effect of the two-way (particle-flow) interaction has been studied and quantified using the notion of distributed chaos and the results of numerical simulations and laboratory measurements. It is shown, in particular, that…

Fluid Dynamics · Physics 2023-09-07 A. Bershadskii

The influence of cohesion among members of dyads is investigated in scenarios characterized by uni-directional flow by means of a discrete model: a corridor and the egress from a room with a bottleneck of varying width are simulated. The…

Multiagent Systems · Computer Science 2017-11-01 Luca Crociani , Yiping Zeng , Andrea Gorrini , Giuseppe Vizzari , Weiguo Song

Direct numerical simulations (DNS) indicate that at large values of the Rayleigh number ($Ra$) convection in porous media self-organizes into narrowly-spaced columnar flows, with more complex spatiotemporal features being confined to…

Fluid Dynamics · Physics 2018-08-01 Baole Wen , Gregory P. Chini

Granular flow dynamics on a vertically vibrated pile is studied by means of both laboratory experiments and numerical simulations. As already revealed, the depth-averaged velocity of a fully-fluidized granular pile under strong vibration,…

Soft Condensed Matter · Physics 2019-06-12 Daisuke Tsuji , Michio Otsuki , Hiroaki Katsuragi

Soliton models are used in elementary particle physics and nuclear physics to model extended objects such as nucleons, using effective field theories derived from more fundamental theories such as QCD. Computer simulation requires some sort…

High Energy Physics - Theory · Physics 2007-05-23 George Jaroszkiewicz , Vladimir Nikolaev