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Efficient multiphysics models that can adapt to the varying complexity of physical processes in space and time are desirable for modeling fluid migration in the subsurface. Vertical equilibrium (VE) models are simplified mathematical models…

Computational Physics · Physics 2018-08-24 Beatrix Becker , Bo Guo , Karl Bandilla , Michael A. Celia , Bernd Flemisch , Rainer Helmig

This paper is concerned with the inhomogeneous incompressible Euler system. We establish a Duchon--Robert type approximation theorem for the distribution describing the local energy flux of bounded solutions. The velocity field is assumed…

Analysis of PDEs · Mathematics 2024-12-13 Marco Inversi , Alessandro Violini

Many living and physical systems such as cell aggregates, tissues or bacterial colonies behave as unconventional systems of particles that are strongly constrained by volume exclusion and shape interactions. Understanding how these…

Quantitative Methods · Quantitative Biology 2026-05-20 Antoine Diez , Jean Feydy

Various microphysical models attempt to explain the occurrence of broad droplet size distributions (DSD) in clouds through approximate representations of the stochastic droplet growth by condensation in a turbulent environment. This work…

Fluid Dynamics · Physics 2025-01-16 G. C. Abade

This study introduces a novel point-wise diffusion model that processes spatio-temporal points independently to efficiently predict complex physical systems with shape variations. This methodological contribution lies in applying forward…

Computational Physics · Physics 2025-08-05 Jiyong Kim , Sunwoong Yang , Namwoo Kang

When addressing spatial biological questions using mathematical models, symmetries within the system are often exploited to simplify the problem by reducing its physical dimension. In a reduced-dimension model molecular movement is…

Quantitative Methods · Quantitative Biology 2025-02-17 Natasha S. Savage

This article considers non-stationary incompressible linear fluid equations in a moving domain. We demonstrate the existence and uniqueness of an appropriate weak formulation of the problem by making use of the theory of time-dependent…

Analysis of PDEs · Mathematics 2023-10-26 Ana Djurdjevac , Carsten Gräser , Philip J. Herbert

For a model convection-diffusion problem, we address the presence of oscillatory discrete solutions, and study difficulties in recovering standard approximation results for its solution. We justify the presence of non-physical oscillations…

Numerical Analysis · Mathematics 2026-01-15 Constantin Bacuta

We construct four variants of space-time finite element discretizations based on linear tensor-product and simplex-type finite elements. The resulting discretizations are continuous in space, and continuous or discontinuous in time. In a…

Numerical Analysis · Mathematics 2024-09-05 Max von Danwitz , Igor Voulis , Norbert Hosters , Marek Behr

In three space dimensions, we consider the compressible inviscid model describing the time evolution of two fluids sharing the same velocity and enjoying the algebraic pressure closure. By employing the technique of convex integration, we…

Analysis of PDEs · Mathematics 2019-12-24 Yang Li , Ewelina Zatorska

Vertical equilibrium models have proven to be well suited for simulating fluid flow in subsurface porous media such as saline aquifers with caprocks. However, in most cases the dimensionally reduced model lacks the accuracy to capture the…

Fluid Dynamics · Physics 2024-05-29 Ivan Buntic , Martin Schneider , Bernd Flemisch , Rainer Helmig

Advective trapping occurs when solute enters low velocity zones in heterogeneous porous media. Classical local modeling approaches combine the impact of slow advection and diffusion into a hydrodynamic dispersion coefficient and many…

Fluid Dynamics · Physics 2020-12-02 Juan J. Hidalgo , Insa Neuweiler , Marco Dentz

Score-based diffusion models have demonstrated remarkable empirical success in learning high-dimensional distributions, particularly those exhibiting low-dimensional and multi-modal structures. However, theoretical understanding of their…

Machine Learning · Statistics 2026-05-29 Jingda Wu , Changxiao Cai

The generally held view that a model of large-scale structure, formed by collisionless matter in the Universe, can be based on the matter model ``dust'' fails in the presence of multi-stream flow, i.e., velocity dispersion. We argue that…

Astrophysics · Physics 2011-05-23 Thomas Buchert , Alvaro Dominguez

While efficient distribution learning is no doubt behind the groundbreaking success of diffusion modeling, its theoretical guarantees are quite limited. In this paper, we provide the first rigorous analysis on approximation and…

Machine Learning · Statistics 2023-03-06 Kazusato Oko , Shunta Akiyama , Taiji Suzuki

Several problems in machine learning are naturally expressed as the design and analysis of time-evolving probability distributions. This includes sampling via diffusion methods, optimizing the weights of neural networks, and analyzing the…

Optimization and Control · Mathematics 2026-05-28 Gabriel Peyré

Diffusion models have achieved remarkable success in generative modeling. Despite more stable training, the loss of diffusion models is not indicative of absolute data-fitting quality, since its optimal value is typically not zero but…

Machine Learning · Computer Science 2026-04-17 Yixian Xu , Shengjie Luo , Liwei Wang , Di He , Chang Liu

Turbulent convection models are thought to be good tools to deal with the convective overshooting in the stellar interior. However, they are too complex to be applied in calculations of stellar structure and evolution. In order to…

Solar and Stellar Astrophysics · Physics 2013-07-16 Q. S. Zhang , Y. Li

Patient-specific computational modeling is a popular, non-invasive method to answer medical questions. Medical images are used to extract geometric domains necessary to create these models, providing a predictive tool for clinicians.…

We study the combined effects of natural convection and rotation on the dissolution of a solute in a solvent-filled circular cylinder. The density of the fluid increases with the increasing concentration of the dissolved solute, and we…

Fluid Dynamics · Physics 2026-04-14 Subhankar Nandi , Jiten C. Kalita , Sanyasiraju VSS Yedida , Satyajit Pramanik