Running CFDDFC with the Azure Console
- Launch a Virtual Machine
- Connect to a Virtual Machine
- Connect with the Remote Desktop
Problem with these instructions? Please send a CFDDFC Support Query.
Logging in with SSH
After you launch a VM, you can connect to it securely using SSH as described below. On connecting through SSH, the user is greeted with a welcome message and presented with the terminal prompt.
For Linux and Mac OS X, open a terminal window and type the following replacing user
with the chosen user name and XXX.XXX.XXX.XXX
with the IP address of the VM,
ssh user@XXX.XXX.XXX.XXX
MS Windows users can connect using PuTTY. This involves:
- download and installation of the PuTTY client;
- conversion of the private key file using PuTTYgen;
- and, starting a PuTTY session.
Setting the Environment
After logging in, the user should set the environment for running OpenFOAM, as follows.
- Find the OpenFOAM installation directory by typing
ls -d /opt/openfoam*
- This should return a directory name like
/opt/openfoam4
- Add the sourcing of the
bashrc
file in the OpenFOAM installation to the user’s.bashrc
(note the dot “.”) file byecho "source /opt/openfoam4/etc/bashrc" >> $HOME/.bashrc
- Source the
.bashrc
(note the dot “.”) filesource .bashrc
- Make the
$FOAM_RUN
directorymkdir -p $FOAM_RUN
The OpenFOAM Configuration
OpenFOAM is a collection of 200+ applications that can be executed from the terminal prompt. The applications include: “solvers” that solve equations to simulate fluid flow; and, “utilities” that perform other tasks needed in CFD, e.g. generation of the computational mesh, initialisation of fields, data manipulation, etc. The applications can be executed from the terminal prompt, reading from and writing to data files of the problem case. In OpenFOAM, the case files are stored within a directory, whose name reflects the problem being simulated, in which there are typically 3 further directories, named 0
, system
and constant
containing the case files. Users unfamiliar with Linux can consult our OpenFOAM Linux Guide.
In the OpenFOAM configuration, an environment variable named $FOAM_RUN
is reserved to represent a default directory to put OpenFOAM case data. The default directory is $HOME/OpenFOAM/USER-VERSION/run
, i.e. $HOME/OpenFOAM/ubuntu-3.0.0/run
for USER=ubuntu
and version number VERSION=3.0.0
. There is also an alias named run
that changes directory (cd
) to the $FOAM_RUN
directory. The OpenFOAM installation can be found in the /opt
directory and example cases are stored in a directory named tutorials
within the installation. Another environment variable $FOAM_TUTORIALS
is set to represent the tutorials
directory.
Testing OpenFOAM
Users can test an example simulation of steady, incompressible, turbulent flow over a backward facing step, named the pitzDaily
after authors of a report on experimental data to which the case relates. The test involves 5 steps:
- changing to the
$FOAM_RUN
directory with therun
alias; - copying the
pitzDaily
case files from thetutorials
directory to the current directory (denoted in Linux as ‘.')
; - changing to the
pitzDaily
case directory; - generating a mesh for the backward step geometry with the
blockMesh
utility; - running the
simpleFoam
solver for steady, incompressible, turbulent flow
Execution these steps from the terminal prompt is as follows:
run cp -r $FOAM_TUTORIALS/incompressible/simpleFoam/pitzDaily . cd pitzDaily blockMesh simpleFoam
For more information about running cases, see:
Configuring OpenFOAM Applications
Solvers and utilities are configured through the data files in a case directory. The configuration of a case can be modified by opening a file in a text editor, changing settings and saving the file. 3 popular editors which can work through a terminal are:
nano
: the easiest of the 3 editors for the purpose, seenano
basics guide;emacs
: powerful editor that uses a more complex set of key commands,emacs
basics;vim
: another editor with arguably a less familiar set of key commands, seevim
quick guide.
It is worth knowing the command to exit the editor you use in case a problem arises:
nano
exits withC-x
(C
=Control key)emacs
exits withC-x C-c
(preceded byC-g
, if needed)emacs
exits withESC :q!
The user may, for example, open the fvSolution
file in the system
directory in one of these editors, e.g. nano
by
nano system/fvSolution
The user may edit the residualControls
as follows, then exit with C-x
, saving the file (Y
)
residualControl { p 1e-3; U 1e-4; "(k|epsilon|omega|f|v2)" 1e-4; }
The user can then restart simpleFoam
from the previous solution. For more information about configuration of case files, see:
Transferring Data to/from the Cloud
The user will likely at some point wish to copy data files to and from Azure. On Linux and Mac OS X data can be transferred by accessing VMs with Linux secure copy (scp
). Copying a file named foo.txt
from the home directory on the VM back to the local machine would be:
scp user@XXX.XXX.XXX.XXX:~/foo.txt .
Copying a file from the local machine to the home directory of the VM would be:
scp foo.txt user@XXX.XXX.XXX.XXX:~/
MS Windows users have an equivalent option with PuttY secure copy (pscp
)