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Streamflow is a dynamical process that integrates water movement in space and time within basin boundaries. The authors characterize the dynamics associated with streamflow time series data from about seventy-one U.S. Geological Survey…

Physics and Society · Physics 2021-04-14 Ganesh R. Ghimire , Navid Jadidoleslam , Witold F. Krajewski , Anastasios A. Tsonis

Robots reason about the environment through dedicated representations. Popular choices for dense representations exploit Truncated Signed Distance Functions (TSDF) and Octree data structures. However, TSDF provides a projective or…

Robotics · Computer Science 2024-12-13 Lan Wu , Cedric Le Gentil , Teresa Vidal-Calleja

Graph Neural Networks (GNNs) have achieved significant success in learning better representations by performing feature propagation and transformation iteratively to leverage neighborhood information. Nevertheless, iterative propagation…

Machine Learning · Computer Science 2021-08-26 Yu Wang , Tyler Derr

The observed convective flows on the photosphere (e.g., supergranulation, granulation) play a key role in the Babcock-Leighton (BL) process to generate large-scale polar fields from sunspots fields. In most surface flux transport (SFT) and…

Solar and Stellar Astrophysics · Physics 2018-09-17 Gopal Hazra , Mark Miesch

We present arguments which show that in all likelihood mesogranulation is not a true scale of solar convection but the combination of the effects of both highly energetic granules, which give birth to strong positive divergences (SPDs)…

Astrophysics · Physics 2009-10-31 M. Rieutord , T. Roudier , J. M. Malherbe , F. Rincon

The fragmentation of shocked flows in a thermally bistable medium provides a natural mechanism to form turbulent cold clouds as precursors to molecular clouds. Yet because of the large density and temperature differences and the range of…

Astrophysics of Galaxies · Physics 2015-05-27 Fabian Heitsch , Thorsten Naab , Stefanie Walch

We present high resolution simulations of two-fluid (ion-neutral) MHD turbulence with resolutions as large as 512^3. The simulations are supersonic and mildly sub-Alfvenic, in keeping with the conditions present in molecular clouds. Such…

Astrophysics of Galaxies · Physics 2015-06-16 Chad D. Meyer , Dinshaw S. Balsara , Blakesley Burkhart , Alex Lazarian

Solar active regions (ARs) are thought to be formed by magnetic fields from the convection zone. Our flux emergence simulations revealed that a strong horizontal divergent flow (HDF) of unmagnetized plasma appears at the photosphere before…

Solar and Stellar Astrophysics · Physics 2015-06-22 Shin Toriumi , Keiji Hayashi , Takaaki Yokoyama

Magneto-convection simulations on meso-granule and granule scales near the solar surface are used to study small scale dynamo activity, the emergence and disappearance of magnetic flux tubes, and the formation and evolution of micropores.…

Astrophysics · Physics 2007-05-23 Robert F. Stein , Aake Nordlund

This paper introduces a novel approach to embed flow-based models with hierarchical structures. The proposed framework is named Variational Flow Graphical (VFG) Model. VFGs learn the representation of high dimensional data via a…

Machine Learning · Statistics 2022-07-07 Shaogang Ren , Belhal Karimi , Dingcheng Li , Ping Li

Using turbulent MHD simulations (magnetic Reynolds numbers up to 8000) and Hinode observations, we study effects of turbulence on measuring the solar magnetic field outside active regions. Firstly, from synthetic Stokes V profiles for the…

Astrophysics · Physics 2011-02-11 Jonathan Pietarila Graham , Sanja Danilovic , Manfred Schuessler

The aim of this work is to identify the physical processes that occur in the network and contribute to its dynamics and heating. We model the network as consisting of individual flux tubes with a non-potential field structure that are…

Astrophysics · Physics 2009-11-10 S. S. Hasan , A. A. van Ballegoiijen , W. Kalkofen , O. Steiner

The structure and dynamics of small vertical photospheric magnetic flux concentrations has been often treated in the framework of an approximation based upon a low-order truncation of the Taylor expansions of all quantities in the…

Solar and Stellar Astrophysics · Physics 2010-11-02 L. Yelles Chaouche , S. K. Solanki , M. Schuessler

Solid aggregates in turbulent suspensions may break under the action of shear stresses. We explore the use of Graph Neural Networks (GNN) to infer aggregate fragmentation once the aggregate structure and flow velocity gradients are known.…

We have studied forced turbulence of compressible magnetohydrodynamic (MHD) flows through two-dimensional simulations with different numerical resolutions. First, hydrodynamic turbulence with Mach number $<M_s >_{\rm init} \equiv < v >_{\rm…

Astrophysics · Physics 2009-11-07 Hyesook Lee , Dongsu Ryu , Jongsoo Kim , T. W. Jones , Dinshaw Balsara

The aim of this work is to give new observational constraints on solar surface flows by determining the horizontal scale dependence of the velocity and intensity fields, as represented by their power spectra, and to offer some theoretical…

Solar and Stellar Astrophysics · Physics 2015-05-14 M. Rieutord , T. Roudier , F. Rincon , J. -M. Malherbe , N. Meunier , T. Berger , Z. Frank

A filtered density function (FDF) model based on deep neural network (DNN), termed DNN-FDF, is introduced for large eddy simulation (LES) of turbulent flows involving conserved scalar transport. The primary objectives of this study are to…

Fluid Dynamics · Physics 2023-10-02 Shubhangi Bansude , Reza Sheikhi

The Tisserand graph (TG) is a graphical tool commonly employed in the preliminary design of gravity-assisted trajectories. The TG is a two-dimensional map showing essential orbital information regarding the Keplerian orbits resulting from…

Earth and Planetary Astrophysics · Physics 2021-04-02 D. de la Torre Sangrà , E. Fantino , R. Flores , O. Calvente Lozano , C. García Estelrich

Exploring and modeling rain generation mechanism is critical for augmenting paired data to ease training of rainy image processing models. Against this task, this study proposes a novel deep learning based rain generator, which fully takes…

Computer Vision and Pattern Recognition · Computer Science 2024-04-30 Zhiqiang Pang , Hong Wang , Qi Xie , Deyu Meng , Zongben Xu

Fractal grids generate turbulence by exciting many length scales of different sizes simultaneously rather than using the nonlinear cascade mechanism to obtain multi-scale structures, as it is the case for regular grids. The interest in…

Fluid Dynamics · Physics 2022-10-13 André Fuchs , Wided Medjroubi , Hannes Hochstein , Gerd Gülker , Joachim Peinke