Filters








3,841 Hits in 2.4 sec

Density-PDFs and Lagrangian statistics of highly compressible turbulence

Ch. Beetz, Ch. Schwarz, J. Dreher, R. Grauer
2008 Physics Letters A  
Numerical simulations were performed with 512^3 collocation points and 2 million tracer particles integrated over several dynamical times.  ...  We report on probability-density-functions (PDF) of the mass density in numerical simulations of highly compressible hydrodynamic flows and the corresponding structure formation of Lagrangian particles  ...  -We'd like to acknowledge interesting discussions with R. Friedrich and J. Schumacher. Computations were performed on a Linux-Opteron cluster supported by HBFG-108-291.  ... 
doi:10.1016/j.physleta.2008.01.009 fatcat:s6urnqpdqvd6vfx6dunfff7yvy

Interaction of fluids with deformable solids

Matthias Müller, Simon Schirm, Matthias Teschner, Bruno Heidelberger, Markus Gross
2004 Computer Animation and Virtual Worlds  
In this paper, we present a method for simulating the interaction of fluids with deformable solids.  ...  The method we describe in this paper models the exchange of momentum between Lagrangian particle-based fluid models and solids represented by polygonal meshes.  ...  In this paper we concentrate on Lagrangian methods because they allow fluids with free surfaces to move freely in space while in the Eulerian case fluid computations are restricted to a spatially fixed  ... 
doi:10.1002/cav.18 fatcat:suhjaxxtmbcvfh4hymxxr7qbzu

Long Time Correlations in Lagrangian Dynamics: A Key to Intermittency in Turbulence

N. Mordant, J. Delour, E. Léveque, A. Arnéodo, J.-F. Pinton
2002 Physical Review Letters  
New aspects of turbulence are uncovered if one considers flow motion from the perspective of a fluid particle (known as the Lagrangian approach) rather than in terms of a velocity field (the Eulerian viewpoint  ...  It enables us to approach intermittency in turbulence from a dynamical point of view and to analyze the Lagrangian velocity fluctuations in the framework of random walks.  ...  The flow volume is continuously insonified with a monochromatic ultrasound which is then scattered by the tracer particle [7] .  ... 
doi:10.1103/physrevlett.89.254502 pmid:12484891 fatcat:kfilqlzukjejliwe5cwerbryxu

A Review of Some Monte Carlo Simulation Methods for Turbulent Systems

Peter R. Kramer
2001 Monte Carlo Methods and Applications  
We provide a brief overview of some Monte Carlo methods which have been used to simulate systems with a turbulent fluid component.  ...  The main aim of this article is to expose these novel simulation approaches to turbulent and complex fluid systems to a broader readership familiar with stochastic processes and to provide some pointers  ...  We close this brief introductory review in Section 5 with some general remarks about the comparative utility of the Eulerian fluid and purely Lagrangian simulation approaches for turbulent systems.  ... 
doi:10.1515/mcma.2001.7.3-4.229 fatcat:y7xk2moucrh3flidia7b5qo3em

Impact of the floating-point precision and interpolation scheme on the results of DNS of turbulence by pseudo-spectral codes

Holger Homann, Jürgen Dreher, Rainer Grauer
2007 Computer Physics Communications  
The interpolation scheme for obtaining velocity values at particle positions has a noticeable impact on the Lagrangian acceleration statistics.  ...  In this paper we investigate the impact of the floating-point precision and interpolation scheme on the results of direct numerical simulations (DNS) of turbulence by pseudo-spectral codes.  ...  To analyze the impact of differing single particle trajectories on the statistics of an ensemble of fluid elements we computed the PDFs of the Lagrangian acceleration (acceleration of fluid elements),  ... 
doi:10.1016/j.cpc.2007.05.019 fatcat:cvsskmzpd5dhvf3sulijbem6ju

Neural UpFlow: A Scene Flow Learning Approach to Increase the Apparent Resolution of Particle-Based Liquids [article]

Bruno Roy, Pierre Poulin, Eric Paquette
2021 arXiv   pre-print
Using this interpolation approach and the predicted displacements, our approach combines the input liquid properties with the predicted motion to infer semi-Lagrangian advection.  ...  We also propose a particle-based approach to interpolate between liquids generated from varying simulation discretizations using a state-of-the-art bidirectional optical flow solver method for fluids in  ...  Another work on convolutional networks for Lagrangian fluids has been presented by Ummenhofer et al. [2019] .  ... 
arXiv:2106.05143v1 fatcat:yzb76xpbrrbstnyi6c7nwqnvby

Surface tension models for a multi-material ALE code with AMR

Wangyi Liu, Alice Koniges, Kevin Gott, David Eder, John Barnard, Alex Friedman, Nathan Masters, Aaron Fisher
2017 Computers & Fluids  
Based on the results, the height function approach using volume fractions was chosen to simulate droplet dynamics associated with extreme ultraviolet (EUV) lithography.  ...  A number of surface tension models have been implemented in a 3D multi-physics multi-material code, ALE-AMR, which combines Arbitrary Lagrangian Eulerian (ALE) hydrodynamics with Adaptive Mesh Refinement  ...  Introduction A traditional means of modeling plasma in the high energy density regime is through a fluid description with an ALE (Arbitrary Lagrangian Eulerian) methodology, due to the Lagrangian formulation's  ... 
doi:10.1016/j.compfluid.2017.01.016 fatcat:emngqtpdsbchlpoj2qd2cll7wi

PDE methods in flow simulation post processing

Joachim Becker, Tobias Preusser, Martin Rumpf
2000 Computing and Visualization in Science  
Lagrangian coordinates are computed solving the corresponding linear transport equations numerically.  ...  Therefore, many important properties are naturally established already in the continuous model.  ...  Frank Koster from Bonn University, Eberhard Bänsch from Bremen University and Klaus Johannsen from Stuttgart University for providing the incompressible flow data sets, respectively the porous media simulation  ... 
doi:10.1007/pl00013547 fatcat:mqo2vc4punffjkujgla5knihmy

Physics-Guided Deep Learning for Dynamical Systems: A Survey [article]

Rui Wang, Rose Yu
2021 arXiv   pre-print
In this paper, we provide a structured overview of existing methodologies of integrating prior physical knowledge or physics-based modeling into DL, with a special emphasis on learning dynamical systems  ...  For instance, [114] designed a deep encoder-processor-decoder graphic architecture for simulating fluid dynamics under Lagrangian description.  ...  For example, [127] replaced the numerical solver for solving possion equations with convolution networks in the procedure of Eulerian fluid simulation, and the obtained results are realistic and showed  ... 
arXiv:2107.01272v4 fatcat:bpo6uvrnsffghigaxq7oaixkba

Comparison of Lagrangian and Eulerian frames of passive scalar turbulent mixing

Paul Götzfried, Mohammad S. Emran, Emmanuel Villermaux, Jörg Schumacher
2019 Physical Review Fluids  
with respect to the whole simulation domain.  ...  Model prediction with and without self-convolution and numerical data of the scalar distributions agree qualitatively, however with quantitative differences particularly for small scalar concentrations  ...  ACKNOWLEDGMENTS The work was supported by the Deutsche Forschungsgemeinschaft (DFG) in Germany and the Agence Nationale de la Recherche (ANR) in France with the joint grant TurbMix with Grants No.  ... 
doi:10.1103/physrevfluids.4.044607 fatcat:b4j5sriewvd6zihsrinahugw7i

Accelerating Eulerian Fluid Simulation With Convolutional Networks [article]

Jonathan Tompson, Kristofer Schlachter, Pablo Sprechmann, Ken Perlin
2017 arXiv   pre-print
We use a Convolutional Network with a highly tailored architecture, trained using a novel unsupervised learning framework to solve the linear system.  ...  Efficient simulation of the Navier-Stokes equations for fluid flow is a long standing problem in applied mathematics, for which state-of-the-art methods require large compute resources.  ...  There are two main computational approaches for simulating these equations: the Lagrangian methods, that approximate continuous quantities using discrete moving particles (Gingold & Monaghan, 1977) ,  ... 
arXiv:1607.03597v6 fatcat:nw4ns5fig5b3voxjiccqtr72hu

Multi-scale initial conditions for cosmological simulations

Oliver Hahn, Tom Abel
2011 Monthly notices of the Royal Astronomical Society  
The method uses an adaptive convolution of Gaussian white noise with a real space transfer function kernel together with an adaptive multi-grid Poisson solver to generate displacements and velocities following  ...  For initial baryon density fields, it is suggested to use the local Lagrangian approximation in order to generate a density field for mesh based codes that is consistent with Lagrangian perturbation theory  ...  All simulations were run on the Orange cluster at KIPAC/SLAC. This work was partially supported by NASA ATFP grant NNX08AH26G, NSF AST-0808398 and NSF AST-0807075.  ... 
doi:10.1111/j.1365-2966.2011.18820.x fatcat:przjbxva6fc53mzzzbt523j7m4

Persistent Lagrangian transport patterns in the northwestern Gulf of Mexico [article]

M. K. Gough, and F. J. Beron-Vera, and M. J. Olascoaga, and J. Sheinbaum, and J. Juoanno, R. Duran
2017 arXiv   pre-print
The significance of the climatological LCSs (cLCSs) is supported with ensemble-mean drifter density evolutions from simulated and historical satellite-tracked drifter trajectories.  ...  Persistent Lagrangian transport patterns at the ocean surface are revealed from Lagrangian Coherent Structures (LCSs) computed from daily climatological surface current velocities in the northwestern Gulf  ...  Summary and Conclusions We have extracted robust Lagrangian transport patterns by computing climatological , ) is the velocity of the fluid, with x and t denoting position and time.  ... 
arXiv:1710.04027v1 fatcat:y64dgq374fd3rlld54kh73qd4y

Accurate Direct Numerical Simulation of Two-Way Coupled Particle-Laden Flows Through the Nonuniform Fast Fourier Transform

Maurizio Carbone, Michele Iovieno
2020 International Journal of Safety and Security Engineering  
An application of the NUFFT to the simulation of a statistically steady and isotropic turbulent flow, laden with inertial particles is presented.  ...  In our implementation, particle momentum and temperature back-reactions on the fluid flow are computed by means of the forward NUFFT with B-spline basis, while the B-spline interpolation is performed as  ...  The mixed Eulerian-Lagrangian approach, which combines the solution of the Navier-Stokes equations (NSE) on a fixed Eulerian grid with the Lagrangian tracking of the disperse phase, that is a set of point-mass  ... 
doi:10.18280/ijsse.100205 fatcat:kp4j2uoiobfofl66u7jnt35h2m

Deep learning velocity signals allows to quantify turbulence intensity [article]

Alessandro Corbetta, Vlado Menkovski, Roberto Benzi, Federico Toschi
2019 arXiv   pre-print
Turbulence, the ubiquitous and chaotic state of fluid motions, is characterized by strong and statistically non-trivial fluctuations of the velocity field, over a wide range of length- and time-scales,  ...  Lagrangian properties of particles in turbulence. Annual review of fluid mechanics, 41:375-404, 2009.  ...  Lagrangian velocity signals from Direct Numerical Simulations The true Lagrangian velocity signals are obtained from the numerical integration of Lagrangian tracers dynamics evolved on top of a Direct  ... 
arXiv:1911.05718v2 fatcat:y7zewfutjvfzdmx2prlalpl4pe
« Previous Showing results 1 — 15 out of 3,841 results