Processing of a CAD/CAE Jobs in
grid environment using Elmer
Mohamed Hussein A.Razik
GRID Computing Group
LIT LAB
Electronics Group,
Physics Department,
Faculty of Science,
Ain Shams University,
Aim of the Task
 The
aim of my task is to simulate a
physical phenomena which is heat
transfer by using Elmer software and
execute this simulation on the grid
and take the result from the grid
to the PC via user interface.
What is Elmer?

Elmer is a finite element software package
for the solution of partial differential
equation(s),dealing with multiphysical
simulations.

The Elmer package contains solvers for a
variety of mathematical models. The
following list summarizes the capabilities
of Elmer in specialized fields.
Physical models in Elmer
• Heat transfer: models for conduction, radiation and phase
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•
•
•
•
change
Fluid flow: the Navier-Stokes, Stokes and Reynolds equations,
k-" model
Species transport: generic convection-diffusion equation
Elasticity: general elasticity equations, dimensionally reduced
models for plates and shells
Acoustics: the Helmholtz equation
Electromagnetism: electrostatics, magnetostatics, induction
Micro fluidics: slip conditions, the Poisson-Boltzmann equation
Level set method: Euleri an free boundary problems
Quantum Mechanics: density functional theory (Kohn-Sham)
Numerical methods in Elmer

For approximation and linear system solution Elmer offers a
great number of possibilities. The following list summarizes
some of the most essential ones.
• All basic element shapes in 1D, 2D and 3D with the
Lagrange shape functions of degree k 2
• Higher degree approximation using p-elements
• Time integration schemes for the first and second
order equations
• Solution methods for Eigen value problems
• Direct linear system solvers (Lapack & Umfpack)
• Iterative Krylov subspace solvers for linear systems
• ILU preconditioning of linear systems
• Parallelization of iterative methods
• The discontinuous Galerk in method
• Stabilized finite element formulations, including the
methods of residual free bubbles and SUPG
• Adaptively, particularly in 2D
Introduction to Message Passing
Interface (MPI)

What is MPI?
◦ Message Passing Interface
 Message passing is a method by which data from one processor memory
is copied to another processor memory

Why MPI?
◦ MPI library functions enable programmers to write portable codes,
which can run on
 distributed-memory/shared memory multiprocessor machines
 cluster of workstations
9
Parallel processing
Parallel processing is the ability to carry
out
multiple
operations
or
tasks
simultaneously.
 Parallel Processing in Computers
The simultaneous use of more than one
CPU or processor core to execute a
program or multiple computational threads.
Ideally, parallel processing makes programs
run faster because there are more engines
(CPUs or cores) running it.

Parallel Implementation in Elmer
The general concept of a parallel run
within Elmer is displayed in Figure .
 Elmer uses domain decomposition for
distributing the load to multiple processes
that are being run on either different
cores or CPUs. To that end, the initial
mesh has to be split into parts that – with
respect to the applied models – lead to
similar loads of the processors.

Practice on Elmer software
The aim task is to run a simulation
experiment on the grid and this simulation
is worked parallel and take the result and
store it on the pc via user interface.
 We have a physical problem heat
transfer begins with certain boundary
conditions after certain time we study
the heat transfer.

Workflow to create Elmer file

Open your input file (example: samples/grd/angle3d.grd):
Workflow

Optionally configure mesh generator and remesh:
Workflow


The values in the config dialog are inherited from cmd line tools:
As shown in special window
Workflow

Remeshing is perfomed in a separate thread:
Workflow

Manipulate boundaries: Select boundaries by holding down the CTRL-key
while double clicking. Choose ”unify surface” to join:
Workflow


Define an equation (PDE-system) to solve:
As shown in special window
Workflow


Let us define the ”heat equation” as an example:
As shown in special window
Workflow


Similarly, we can next define material properties and parameters:
As shown in special window
Workflow

Add body force:
Workflow

set boundary conditions:
Workflow

Generate solver input file (sif):
Workflow

Save the model:
Workflow

Run solver:
Workflow

Convergence monitor reveals possible problems:
Job submission of Elmer file to the grid
Processing of the data on the grid
Job status
Retrieve job's output
Transfer the result from the grid to the pc via
interface.
Workflow

Visualize the results by Elmer post:
Acknowledgement

I would like to thank:
Alexander Ujhinskiy
Nikolay kutovskiy
For continuous efforts for teaching the aspects and
completing the jobs of the grid. Thanks for sincerely help.
AND
Thanks for supervisors of the school
for help and attentions.
Prof.Dr.Ali Ellithi & Prof.Dr. Ali Khalil
Thank you for your attention
Workflow

Edit the solver input file (if needed):
Workflow

Turn on/off boundary index numbering for verification:
Workflow

Data is given in the ”General” and ”Heat equation”
tabs: