Hi Feng, dear Yade community,
@Feng: Thanks for the link to your homepage. It is interesting to know that somebody already did something similar :-) Btw: Is it correct that Yade is based on a shared memory approach? >I think you and I should be using the same approach originated from Prof. Tsuji? Yes! >1. FVM size/particle size The simulations I did so far were with particle diameter in the same order of magnitude or smaller than the grid spacing. I did not extensively test particles that are much larger than the grid size because my flow problems did not involve such cases. But to my knowledge, this would lead to a) convergence issues and b) possibly malpredictions of the dragforce by standard drag correlations (Gidaspow, DiFelice,...) My maximum ratio cell spacing/particle diameter was ~1/1 which converged and matched the validation experiments well >2. The maximum particle number possible on a cluster It depends on what cluster you have :-) If you look at http://lammps.sandia.gov/bench.html#chute you fill find the rightmost dot in the left figure corresponding to 2 BILLION PARTICLES! >3. The parallel mechanism We are using MPI because we think that the code should be portable to clusters. We have a small cluster (~150 proc.) at our Institute, so for me it is a huge speed-up switching from my workstation to the cluster >4. What kind of problem/type of flow you use in your problem? Typical problems that we are using or intending to use CFD-DEM for is pneumatic conveying, fluidized bed, hopper discharge and die filling. >5. Is it easy to change/create new particle constitution laws for the solid phase? Yes, LAMMPS is written in the intention to be easily modified. A whole section of the documentation is dedicated to this: http://lammps.sandia.gov/doc/Section_modify.html I must admit that currently, LAMMPS is missing a feature to import granular walls from CAD. But I am working on this... >6. Effect of different drag equations I must admit that I did not extensively test that. Afaik, Gidaspow could lead to convergence problems as it is discontinuous in one point. Thus I also used DiFelice but did not find much difference I should add that the simulation experience I am talking about was with a EDEm-FLUENT coupling that I wrote myself. The "LammpsFoam" is now in beta, and this fluidized bed configuration http://lammps.sandia.gov/movies/gran_openfoam.avi is the only case that we calculated with "LammpsFoam" so far. @Feng: It would be nice to know what answer you would give to these 6 questions! Thanks and regards, Christoph ------------------------------------------------------------------- Von: Feng Chen [mailto:fch...@utk.edu] Gesendet: Donnerstag, 08. Oktober 2009 02:18 An: kl...@fluidmech.mechatronik.uni-linz.ac.at; yade-dev@lists.launchpad.net; yade-us...@lists.launchpad.net Betreff: RE: [Yade-dev] Open Source DEM with LAMMPS Hi, Christoph Kloss: I am so glad to see there is another code for DEM-CFD coupling since this has been my PhD topic, I also coupled YADE with OpenFOAM: http://fchen3.googlepages.com/discreteelementmethod I think you and I should be using the same approach originated from Prof. Tsuji? I would be very like to discuss some of the details with you, such as: 1. FVM size/particle size 2. The maximum particle number possible on a cluster 3. The parallel mechanism 4. What kind of problem/type of flow you use in your problem? 5. Is it easy to change/create new particle constitution laws for the solid phase? 6. Effect of different drag equations etc. Thank you for sharing your experience with us!!! Feng Chen -----Original Message----- From: yade-dev-bounces+fchen3=utk....@lists.launchpad.net on behalf of Christoph Kloss Sent: Wed 10/7/2009 6:11 AM To: yade-dev@lists.launchpad.net; yade-us...@lists.launchpad.net Subject: [Yade-dev] Open Source DEM with LAMMPS Dear yade users and developers, I would like to bring the DEM capabilities of LAMMPS to your attention. LAMMPS is an open source molecular dynamics code that also provides possibilities for DEM simulations (thanks to algorithmic and physical analogies). LAMMPS is on the open source "market" since the mid90s. It is thus quite mature, very fast and provides excellent documentation. Please refer to the homepage http://lammps.sandia.gov/ for download and documentation. For some simulation examples, please refer to http://lammps.sandia.gov/movies.html#dem The final movie ( http://lammps.sandia.gov/movies/gran_openfoam.avi ) shows a new capability that my colleague Christoph Goniva and I have developed to perform CFD-DEM simulations by coupling LAMMPS to the OpenFoam computational fluid dynamics (CFD) package. This allows us to run CFD-DEM simulations on clusters using MPI parallelism. Some more videos and sample input scripts can be found at http://fluid.jku.at/hp/index.php?option=com_docman&task=cat_view&gid=168 LAMMPS is written in C++ and very easy to modify. If you are interested in LAMMPS, you are welcome to contact me! I would be happy if YADE and LAMMPS could profit from each other. Kind regards from Austria, Christoph Kloss -------------------------------------------------------------------- Dipl.-Ing. Christoph Kloss Christian-Doppler Laboratory on Particulate Flow Modelling Institute of Fluid Mechanics and Heat Transfer Johannes Kepler University, Altenbergerstrasse 69, A-4040 Linz/Austria e-mail: christoph.kl...@jku.at phone: +43-(0)732-2468-6476 fax: +43-(0)732-2468-6462 web: fluid.jku.at ------------------------------------------------------------------- _______________________________________________ Mailing list: https://launchpad.net/~yade-dev Post to : yade-dev@lists.launchpad.net Unsubscribe : https://launchpad.net/~yade-dev More help : https://help.launchpad.net/ListHelp _______________________________________________ Mailing list: https://launchpad.net/~yade-dev Post to : yade-dev@lists.launchpad.net Unsubscribe : https://launchpad.net/~yade-dev More help : https://help.launchpad.net/ListHelp