4,178 Hits in 7.8 sec

Development of a coupling between a system thermal-hydraulic code and a reduced order CFD model [article]

S. Kelbij Star, Giuseppe Spina, Francesco Belloni, Joris Degroote
2020 arXiv   pre-print
The velocity transported over a coupling boundary interface is imposed in the ROM using a penalty method. The coupled models are evaluated on open and closed pipe flow configurations.  ...  Also for new parameter sets, the coupled RELAP5/ROM models are capable of predicting the coupled RELAP5/CFD results with good accuracy.  ...  Acknowledgment The authors would like to thank the ITHACA-FV developers and contributors for their input and insightful discussions on the development of reduced order models.  ... 
arXiv:2009.10817v2 fatcat:fgriuq2klfbtzh66js5prvsd6q

An efficient method for simulation of the dynamics of a large number of deformable droplets in the stokes regime

Olga A. Abramova, Yulia A. Itkulova, Nail A. Gumerov, Iskander Sh. Akhatov
2014 Doklady physics (Print)  
ACKNOWLEDGMENTS The study is supported by Grant of Ministry of Education and Science of the Russian Federation (11.G34.31.0040), Grant RFFI no. 12 01 31173, and Fantalgo, LLC (Maryland, USA).  ...  The Krylov subspace projection methods are among the most efficient methods for solution of SLAE. Particularly, in the present paper the general minimal residual method (GMRES) [9] is used.  ...  The developed method can be used for solution of a wide range of problems related to the emulsion flow in micro and nanoscales.  ... 
doi:10.1134/s102833581405005x fatcat:utydh2wykfgude2rhpghohgjau

On adaptive BDDC for the flow in heterogeneous porous media [article]

Bedřich Sousedík
2019 arXiv   pre-print
We study a method based on Balancing Domain Decomposition by Constraints (BDDC) for a numerical solution of a single-phase flow in heterogenous porous media.  ...  Performance of the method is illustrated on the benchmark problem from the 10th SPE Comparative Solution Project (SPE 10).  ...  These trends are in agreement with the qualitative observations made from Figure 6 .5. Conclusion. We studied a method for solution of single-phase flow in heterogeneous porous media.  ... 
arXiv:1901.02090v1 fatcat:6xn5pudhqvcgdnllahd52jg2d4

A bidirectional coupling procedure applied to multiscale respiratory modeling

A.P. Kuprat, S. Kabilan, J.P. Carson, R.A. Corley, D.R. Einstein
2013 Journal of Computational Physics  
In addition we have developed a "pressure-drop" residual which allows for stable coupling of flows between a 3D incompressible CFD application and another (lowerdimensional) fluid system.  ...  In the case of a single residual evaluation per timestep, the method has zero additional computational cost compared to uncoupled or unidirectionally coupled simulations.  ...  Keith Miller for the idea of applying a partial NACCEL correction at the end of a timestep. We also gratefully acknowledge Drs. Robb Glenny and Sudhaker Pipavath, UW for the human CT images.  ... 
doi:10.1016/ pmid:24347680 pmcid:PMC3856712 fatcat:j77ijbn5andirdegsztb6rops4

Lighthouse: A User-Centered Web Service for Linear Algebra Software [article]

Boyana Norris and Sa-Lin Bernstein and Ramya Nair and Elizabeth Jessup
2014 arXiv   pre-print
In the Lighthouse project, we enable developers with varied backgrounds to readily discover and effectively apply the best available numerical software for their problems.  ...  Meanwhile, experts in these domains typically lack the training or time required to develop efficient, high-performance implementations of linear algebra algorithms.  ...  The Janus supercomputer is a joint effort of the University of Colorado Boulder, the University of Colorado Denver, and the National Center for Atmospheric Research.  ... 
arXiv:1408.1363v1 fatcat:wvaptefynbhkjhelihzzxo7f2u

CTLSS-an advanced electromagnetic simulation tool for designing high-power microwave sources

M. Basten, D.R. Whaley, T.H. McClure, D.P. Chernin, T.M. Antonsen, B. Levush, A. Mondelli, S.J. Cooke
2000 IEEE Transactions on Plasma Science  
The electromagnetic simulation engine in CTLSS has been designed and implemented as a volumetric frequency-domain model that can handle both resonant eigenvalue problems, using the Jacobi-Davidson algorithm  ...  Currently, this link has been implemented for helix traveling-wave tubes (TWT's) only, using the CHRISTINE code as the large-signal model, but a new, general, large-signal model is under development and  ...  Subspace projection methods represent a general class of methods for the solution of large eigensystems.  ... 
doi:10.1109/27.887737 fatcat:cv7fzpad4rhjxhndsx35aup3za

Application of the parallel BDDC preconditioner to the Stokes flow

Jakub Šístek, Bedřich Sousedík, Pavel Burda, Jan Mandel, Jaroslav Novotný
2011 Computers & Fluids  
It is successfully applied to several problems of Stokes flow discretized by Taylor-Hood finite elements and BDDC is shown to be a promising method also for this class of problems.  ...  A parallel implementation of the Balancing Domain Decomposition by Constraints (BDDC) method is described. It is based on formulation of BDDC with global matrices without explicit coarse problem.  ...  JakubŠístek also thanks to the European Science Foundation OPTPDE (Optimization with PDE Constraints) Network for the financial support of attending the 10th ICFD Conference on Numerical Methods for Fluid  ... 
doi:10.1016/j.compfluid.2011.01.002 fatcat:drspb7dodzbxha2vxczt7fsteq

Perspective on Eulerian Finite Volume Methods for Incompressible Interfacial Flows [chapter]

D. B. Kothe
1998 Free Surface Flows  
In the following, many algorithms are reviewed brie y and commented on, but special attention is paid to projection methods for the incompressible NS equations, volume tracking methods for interface kinematics  ...  Interfaces present in these ows possess topologies that are not only irregular but also dynamic, undergoing gross changes such as merging, tearing, and lamenting as a result of the ow and interface physics  ...  In approximate projection methods, the discrete projection operator does not necessarily algebraically match the conditions for being a projection.  ... 
doi:10.1007/978-3-7091-2598-4_6 fatcat:cpbtn56zbvcglbpklk6tadokd4

A finite element based level set method for two-phase incompressible flows

Sven Groß, Volker Reichelt, Arnold Reusken
2006 Computing and Visualization in Science  
We present a method that has been developed for the efficient numerical simulation of two-phase incompressible flows. For capturing the interface between the flows the level set technique is applied.  ...  For reparametrization of the level set function a new variant of the Fast Marching method is introduced.  ...  routines that are implemented for a one-phase flow problem can be reused both for the Navier-Stokes part and for the advection equation.  ... 
doi:10.1007/s00791-006-0024-y fatcat:sgnphnwsz5f3fida3n6sybxuwa

Validated simulation of droplet sedimentation with finite-element and level-set methods

Evangelos Bertakis, Sven Groß, Jörg Grande, Oliver Fortmeier, Arnold Reusken, Andreas Pfennig
2010 Chemical Engineering Science  
The finite-element and the extended finite-element methods were implemented and compared. The level-set function is used for capturing the interface movement.  ...  The three-dimensional instationary simulations included the stages of drop acceleration, deformation, and stability in terms of shape and velocity.  ...  Acknowledgement This project was funded by the German Research Foundation (DFG) in the framework of the collaborative research centre CRC 540 "Model-based Experimental Analysis of Kinetic Phenomena in  ... 
doi:10.1016/j.ces.2009.11.043 fatcat:jcqfu2dl7rap5fnyhtl7g26gkm

A consistent rescaled momentum transport method for simulating large density ratio incompressible multiphase flows using level set methods

S Ghods, M Herrmann
2013 Physica Scripta  
damped surface wave, and the collapse of a water column in air under ambient conditions.  ...  We present results obtained with the new method for a number of high-density ratio test cases, including the advection of a 1,000,000:1 density ratio impulsively accelerated drop, a 1000:1 density ratio  ...  The authors would also like to thank M. Raessi, O. Desjardins, and F. Ham for many helpful discussions.  ... 
doi:10.1088/0031-8949/2013/t155/014050 fatcat:rfeg2h4jovbk7mixdrc4iamwwq

The Immersed Boundary Method: Application to Two-Phase Immiscible Flows

Avihai Spizzichino, Sharone Goldring, Yuri Feldman
2019 Communications in Computational Physics  
Further, we present a grid independence study and extensive verification of the developed method for representative 2D two-phase flows dominated by buoyancy, shear stress, and surface tension forces.  ...  In this paper we present an extended formulation of the immersed boundary (IB) method that facilitates simulation of incompressible immiscible two-phase flows.  ...  An additional contribution to the development of the fully coupled DLM approach was due to the work of Taira and Colonius [32] , who implemented it within the framework of a projection method.  ... 
doi:10.4208/cicp.oa-2018-0018 fatcat:4y26ey7yljdqxjynsdzlbdfmbm

Petascale algorithms for reactor hydrodynamics

P Fischer, J Lottes, D Pointer, A Siegel
2008 Journal of Physics, Conference Series  
We describe recent algorithmic developments that have enabled large eddy simulations of reactor flows on up to P = 65, 000 processors on the IBM BG/P at the Argonne Leadership Computing Facility.  ...  Computer time on the Argonne Leadership Computing Facility was provided through a 2008 DOE Office of Science INCITE Award.  ...  We thank Hank Childs and David Bremer from the LLNL VisIt group for assistance with graphics and data analysis Scott Parker at the ALCF for assistance with BG/P, and Stefan Kerkemeier of ETH, Zurich, for  ... 
doi:10.1088/1742-6596/125/1/012076 fatcat:gfxgpvidjvcw5ncg5viuchd4me

Partitioned semi-implicit methods for simulation of biomechanical fluid-structure interaction problems

A Naseri, O Lehmkuhl, I Gonzalez, A Oliva
2016 Journal of Physics, Conference Series  
Numerical tests are conducted in the context of a biomechanical problem.  ...  Fixed-point solver with Aitken's relaxation method also proved to be a simple, yet efficient method for FSI simulations.  ...  This idea was first proposed in [10] and later used in [11, 12] . The pressure stress term is split off by using a fractional step projection method for fluid flow equations.  ... 
doi:10.1088/1742-6596/745/3/032020 fatcat:lcbmybe4pfh7hketys34bw5pqe

Sharp Interface Algorithm for Large Density Ratio Incompressible Multiphase Magnetohydrodynamic Flows

Tongfei Guo, Shuqiang Wang, Roman Samulyak
2013 Procedia Computer Science  
The algorithm employs the method of front tracking for the propagation of material interfaces and the embedded interface method for solving elliptic-parabolic problems associated with approximations of  ...  A numerical algorithm and the corresponding paralleled implementation for the study of magnetohydrodynamics (MHD) of large density ratio, three-dimensional multiphase flows at low magnetic Reynolds numbers  ...  Acknowledgments: This work was supported in part by the Muon Accelerator Program of the US Department of Energy.  ... 
doi:10.1016/j.procs.2013.05.215 fatcat:6avl7cx6yvcy3bjkhucjpgzs6i
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