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The micro-continuum method is a novel approach to simulate flow and transport in multiscale porous materials. For such materials, the domain can be divided into three sub-domains depending on the local porosity {\epsilon}: fully resolved…

Fluid Dynamics · Physics 2024-05-13 Julien Maes , Hannah Menke

This article proves the existence of solutions to a model of incompressible miscible displacement through a porous medium, with zero molecular diffusion and modelling wells by spatial measures. We obtain the solution by passing to the limit…

Analysis of PDEs · Mathematics 2017-02-01 Jerome Droniou , Kyle S. Talbot

Forecasting ocean drift trajectories are important for many applications, including search and rescue operations, oil spill cleanup and iceberg risk mitigation. In an operational setting, forecasts of drift trajectories are produced based…

Computation · Statistics 2020-03-26 Håvard Heitlo Holm , Martin Lilleeng Sætra , Peter Jan van Leeuwen

We consider a stabilized nonconforming finite element method for data assimilation in incompressible flow subject to the Stokes' equations. The method uses a primal dual structure that allows for the inclusion of nonstandard data. Error…

Numerical Analysis · Mathematics 2016-09-21 Erik Burman , Peter Hansbo

We show how the 3DVAR data assimilation methodology can be used in the astrophysical context of a two-dimensional convection flow. We study the way this variational approach finds best estimates of the current state of the flow from a…

Solar and Stellar Astrophysics · Physics 2013-08-09 Andreas Svedin , Milena C. Cuellar , Axel Brandenburg

We consider nonlinear solvers for the incompressible, steady (or at a fixed time step for unsteady) Navier-Stokes equations in the setting where partial measurement data of the solution is available. The measurement data is…

Numerical Analysis · Mathematics 2024-01-15 Bosco Garcia-Archilla , Xuejian Li , Julia Novo , Leo Rebholz

Current theories of diffusiophoresis in porous media are limited to a porous medium saturated with a valence symmetric electrolyte. A predictive model for diffusiophoresis in porous media saturated with a valence asymmetric electrolyte, or…

Soft Condensed Matter · Physics 2024-12-03 Siddharth Sambamoorthy , Henry C. W. Chu

Compressive sensing(CS) has drawn much attention in recent years due to its low sampling rate as well as high recovery accuracy. As an important procedure, reconstructing a sparse signal from few measurement data has been intensively…

Information Theory · Computer Science 2018-06-25 Yicong He , Fei Wang , Shiyuan Wang , Badong Chen

Bayesian hierarchical Poisson models are an essential tool for analyzing count data. However, designing efficient algorithms to sample from the posterior distribution of the target parameters remains a challenging task for this class of…

Methodology · Statistics 2025-02-10 Aldo Gardini , Fedele Greco , Carlo Trivisano

Recently, significant connections between compressed sensing problems and optimization of a particular class of functions relating to solutions of Hamilton-Jacobi equation was discovered. In this paper we introduce a fast approximate…

Optimization and Control · Mathematics 2013-11-27 Farzin Barekat , Stanley Osher , Jerome Darbon

The increasing prevalence of marine pollution during the past few decades motivated recent research to help ease the situation. Typical water quality assessment requires continuous monitoring of water and sediments at remote locations with…

Machine Learning · Computer Science 2022-03-08 Xiaoting Xu , Tin Lai , Sayka Jahan , Farnaz Farid

This paper presents a novel centralized, variational data assimilation approach for calibrating transient dynamic models in electrical power systems, focusing on load model parameters. With the increasing importance of inverter-based…

Optimization and Control · Mathematics 2023-11-15 Ahmed Attia , D. Adrian Maldonado , Emil Constantinescu , Mihai Anitescu

We present an adaptive smoother for linear state-space models with unknown process and measurement noise covariances. The proposed method utilizes the variational Bayes technique to perform approximate inference. The resulting smoother is…

Systems and Control · Computer Science 2023-07-19 Tohid Ardeshiri , Emre Özkan , Umut Orguner , Fredrik Gustafsson

We investigate two common numerical techniques for integrating reversible moist processes in atmospheric flows in the context of solving the fully compressible Euler equations. The first is a one-step, coupled technique based on using…

Atmospheric and Oceanic Physics · Physics 2015-05-11 Max Duarte , Ann S. Almgren , Kaushik Balakrishnan , John B. Bell , David M. Romps

We prove that the semiflow map associated to the evolution problem for the porous medium equation (PME) is real-analytic as a function of the initial data in $H^s(\mathbb{S})$, $s>7/2,$ at any fixed positive time, but it is not uniformly…

Analysis of PDEs · Mathematics 2017-05-04 Bogdan--Vasile Matioc

This paper deals with simulation of flow and transport in porous media such as transport of groundwater contaminants. We first discuss how macro scale equations are derived and which terms have to be closed by models. The transport of…

Numerical Analysis · Mathematics 2018-07-03 Quanji Cai , Sheema Kooshapur , Michael Manhart , Ralf-Peter Mundani , Ernst Rank , Andreas Springer , Boris Vexler

Relative permeability is commonly used to model immiscible fluid flow through porous materials. In this work we derive the relative permeability relationship from conservation of energy, assuming that the system to be non-ergodic at large…

Simulation of fluid flow in porous media has many applications, from the micro-scale (cell membranes, filters, rocks) to macro-scale (groundwater, hydrocarbon reservoirs, and geothermal) and beyond. Direct simulation of flow in porous media…

Fluid Dynamics · Physics 2020-04-27 Ying Da Wang , Traiwit Chung , Ryan T. Armstrong , Peyman Mostaghimi

Implicit time-stepping for advection is applied locally in space and time where Courant numbers are large, but standard explicit time-stepping is used for the remaining solution which is typically the majority. This adaptively implicit…

Fluid Dynamics · Physics 2024-06-14 Hilary Weller , Christian Kuehnlein , Piotr K. Smolarkiewicz

Simulation-free methods for training continuous-time generative models construct probability paths that go between noise distributions and individual data samples. Recent works, such as Flow Matching, derived paths that are optimal for each…