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Running a case

Download the following Demo file:


Unpack the file by using the following command:

tar -xvozf demo_sep2005.tgz

You will see the following files:

The demo files

  • demo.bnd
  • demo.cel
  • demo.cfg
  • demo.din
  • demo.net
  • demo.vrt

Create Geometry File

Create a geometry file using the preprocessor and the following inputs:

(out)Dolfyn PreProcessor
(out)Input casename:
(out)Using demo as input
(out)Opening demo.dbg
(out)File demo.dbg opened
(out)Opening vertex file
(out)Opening demo.vrt
(out)File demo.vrt opened
(out)Initialise vertex list
(out)Setting up boundary list: 2140
(out)Total number of boundaries: 4140
(out)Default boundaries: 2000
(out)Assigned boundaries: 2140
(out)Done reading geometry
(out)Minimum distance to a wall: 2.4999976E-02
(out)Maximum distance to a wall: 0.1000004
(out)Minimum wall angle (degs) : 0.0000000E+00
(out)Maximum wall angle (degs) : 0.0000000E+00
(out)Enter scaling factor (1.0):
(out)Using: 1.000000
(out)Enter format of geometry file (bin|ascii):
(out)Dump geometry file
(out)Opening demo.geo
(out)File demo.geo opened
The result is the geometry input file for dolfyn demo.geo.

Editing Inputs

Optionally, the input file demo.din may be edited, for example with nedit:

nedit demo.din &

Run dolfyn

Now start dolfyn and select the demo case:

This is dolfyn version 0.300
Copyright(C) 2002-2005 Cyclone Fluid Dynamics BV
NL-5583 XM, Waalre, The Netherlands
Enter case:
Using case: demo
demo.geo binary
Opening geometry file
*** Warning: Geometry file of version: 0.200
Maximum region number found: 6
Geometry checks
Angles: 0.0000000E+00 0.0000000E+00 0
End reading geometry
Boundary 1 inlet conditions
Boundary 2 outlet conditions
Boundary 3 sym. conditions
Boundary 4 wall conditions
Boundary 5 sym. conditions
Boundary 6 wall conditions
Boundary 4 sym. conditions
Boundary 6 sym. conditions
Boundary 0 sym. conditions
End of input deck

Case : demo
Title : Demo test run
Date and time : 09/26/2005 (15:25)
Number of cells : 1000
Number of vertices : 2146
Number of boundaries : 2140
Number of faces : 4070
Number of regions : 6
Number of iterations : 200
Steady state run
Target residual tol. : 2.000E-06
Monitor cell : 1
Pressure ref. cell : 1
Reference pressure : 0.000E+00 Pa
Reference density : 1.200E+00 kg/m3
Molecular viscosity : 1.000E-04 Pa s
Gravity vector : 0.000E+00 0.000E+00 0.000E+00
V SCV gamma urf rtol guess
U: TTF 5.000E-01 7.000E-01 1.000E-01 1.000E+00
V: TTF 5.000E-01 7.000E-01 1.000E-01 0.000E+00
W: FTF 5.000E-01 7.000E-01 1.000E-01 0.000E+00
P: TTF 0.000E+00 2.000E-01 5.000E-02 0.000E+00
k: TTF 0.000E+00 5.000E-01 1.000E-01 0.000E+00
e: TTF 0.000E+00 5.000E-01 1.000E-01 0.000E+00
T: FTF 0.000E+00 5.000E-01 1.000E-01 2.930E+02
S: FTF 0.000E+00 5.000E-01 1.000E-01 0.000E+00


1: 2.50E-06 7.09E-09 0.00E+00 1.58E-06 ...
2: 2.48E-06 3.15E-08 0.00E+00 1.56E-06 ...
3: 2.47E-06 2.40E-08 0.00E+00 1.53E-06 ...

The results are stored in demo.odx.

View Results

Finally start OpenDX to inspect the results (load demo.net in OpenDX):


Have Fun!

Of course you can run your own cases. You will need three geometry files:
  • case.cel
  • case.vrt
  • case.bnd
where case is the name of your case. Also you’ll have to edit the file demo.din and rename it to case.din.
The results are stored in case.geo (generated by the preprocessor) and case.odx with the simulation result(s). Remember the overview of all the files and their relations to the process-flow. The demo files demo.cfg and demo.net are OpenDX configuration and network files. You can adapt these files and rename them, or create your own from scratch. In an OpenDX .net you’ll have to load case.odx which contains the required information. See www.opendx.org for examples and usage of OpenDX.

You need to know what to do. The codes and files are ‘as is’. The software and files are there to give you an impression only without any guarantee whatsoever. Accompanying documentation is (still) unavailable.


Everything here is still under heavy development. Updates and changes are not ruled out; in matter of fact, expected.

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