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Discussion items

1-way coupled code is approx 4000 faster but does not work for non-refinables elements as it needs the extra data

Hao did the test on 4000 particles with new code, the Oomph-part is indeed much faster than the older version, this reduces the total simulation time by approx. 20%.

However, it seems somewhere else is getting heavier and the new run compare to the old run is actually longer. Hao checked with Mitchel on both old and new implementations

and found out the time cost difference on the locate_zeta function in pressure gradient. Think of updating coupling force not every Mercury Timestep to reduce the run time.

 Anthony Thornton and Thomas Weinhart will look at it with Mitchel Post on Wednesday
WhatWhoDetails  
MercuryDPM paperThomasMercruyDPM paper is out now, please cite: https://doi. org/10.1016/j.cpc.2019.107129  
Volume couplingHong
  1. CG functions for volume coupling
  2. Chute system: coupling Marix's mu(I) and DPM
  
Particle-fluid couplingMitchel

actions after time step issue fixed in Mitchel's local code, will be committed soon

Update: coupling at high Reynold's numbers now works if two steps with Re=0 is done

  
Doubly periodicJulius

FreeCooling still fails with two periodic boundaries

  
ParallelisationJuliusWorks now; need to be included in MercuryDPM proper

first; is this because unsteady_newton_solve does not keep the previous time step correctly?

  
Paolo mergeThomas

Trunk USER/Paolo directory currently fails

  
Martin Haustein, FreibergThomasVisits Mo 27.01 to Fri 13.03, will implement a concrete pumping system  
Dariel Hernandez Delfin, NavarraThomasVisits 03.02. to 03.05, will work on non-spherical particles in a chute  
Comparison of codesAnt

Hope that you are doing well.

ISSMGE’s TC105 Geomechnics from Micro to Macro chaired by me is running a DEM round robin test.

https://www.issmge.org/news/tc105-dem-round-robin-test

Can you pass this news to our Powders and Grains colleagues, if possible?

Thanks in advance.

Best wishes,

Update: Hongyang contacted the organisers. He will put the description of the test problem on Jira. They will publish the results without linking the codes to the outputs It will be angle of repose measurement for multisphere particles.

  •  Hongyang will make a JIRA job for this problem.
  •  @all: We need a volunteer to run the test problem

Update: Anthony volunteered, but now has no time for it.

  
External problemsAnt
  • Luca
    • When configuring cmake I get the first error, concerning a CMP0057 error.
      I get rid of it by editing the file Source/CmakeModules/MercuryDocumentation.cmake and commenting the first line (cmake_policy(SET CMP0057 NEW)).
    • in list operator
  • DPM issues.docx
  
Release Coming  
DockerHao

Now the docker is tested on Windows(Enterpirse, with Hyper-V activated), Mac(10.15) and XUbuntu(18.04) with the possibility of sharing the files between the container and the host machine.

The draft instruction is on the confluence page: "Docker Instructions", please take a look and let me know if you have trouble in following that instruction.

Could someone download docker on his Windows(Professional) system and test it?

Hao needs to check if there is a possibility to make docker works also on Windows(Home).

If this is settled, we could use it for the MercuryDPM course.

  Oomphlib coupling speedMitchel

Update: Docker works now, on Win, Mac, Linux, can be used in course

  

Jinja or Jinja2

 

Hao

Do we want to add a python interface to MercuryDPM in the future?

Would be useful to use in combination with GrainLearning.

We also have the Mercury command line interface, but that cannot pass functions.

  
MercuryMonth 

Starts April 20; first week we give the MercuryDPM courses (April 27-May 22)

There is a student from Erlangen (attanded DEM8) who might be interested in writing this interface in the MercuryMonth [from Hao]

  
Mercury VideoHao

Youetta made a video:

  •  h.shi-1 Final Tweaks still missing, remind Youetta
  
MercuryMonthJuan

Documentation needed for:

  •  Advanced tutorials (written by the developers)
  •  New tutorials
  •  Interaction::computeNormalForce
  
ProfilingJulius

Julius wants to use MPIIO for parallel output.

Julius showed profile of Mercury showing that most time is spent in computeForces(p,q). mcount, output is removed. virtual functions are still costly

Parallelisation works now; need to be included in MercuryDPM proper; first in Branch; with OMP library included in MDPM; to be discussed in Julius' meeting

  
 Thomas, Mitchel, HongOomph: Non-dimensionalisation is needed, we need to find out why. Hong uses the output function to produce dimensional output.  
Technician jobAnthony0.2fte of his salary can be used to hire a technician. Any volunteers are welcome. Please contact Anthony.  

Other items discussed:

  • Next meeting, 20 Jan 3 Feb 2020 at 11:00