Yes, you need to select the Inspect
Yes, use
The file data will contain the data as described in the first line of the file, a ``comment'' line starting with #.
If you intend to read the simulation files (to convert them or do
other operations/calculations etc...) I would highly recommend that
you do so through the functions provided by the Gerris library
(gfs_simulation_read() and so on). This way you will not reinvent the
wheel and you will be able to use all the functionalities provided by
the library (traversal of the octree structure, computation of
gradients, interpolations etc...). This would also ensure that your
code is independent of the format changes in the simulation file.
Just to give you an example on how this can bite you:
the GfsOutputSimulation object can be used like this (in simulation
files)
Your code which reads the simulation files would need to know about
this. The gfs_simulation_read() function deals with that for you and
other functions give you easy access to this kind of information (what
variables where contained in the simulation file etc...)
The DivCurl tool in OpenDX works for general grids. You can use it
to compute the vorticity (vector) from the U field returned by
GfsImport, however this will work only for 3D fields.
Good question. No there isn't, short of editing and recompiling the
source code. That would be a nice option to have in the simulation
file.
There is no method to do line averaging at the moment, however there
is a method which averages (or more exactly stores the sum) of a given
variable in time over the whole domain. You can do it like that:
This is probably an artefact of the way the animate command
displays a series of PPM images. What happens is that OutputPPM
generates PPM images which are just big enough to contain all the data
in your simulation e.g. if you use 7 levels of refinement and one box,
OutputPPM will generate images with
128 x 128
The solution is simple, you can set the size of the images generated by OutputPPM using:
Most visualisation packages assume that the data is defined
on either structured Cartesian meshes (this includes curvilinear
coordinates) or fully unstructured meshes (tetrahedra etc...).
The octrees used by Gerris need first to be converted into
unstructured tetrahedra and then imported into OpenDX etc...This is
quite slow and memory-hungry and loses most of the advantages of
the octree: in particular the multilevel representation of the
solution is very useful from a visualisation point of view.
I am not aware of any good visualisation tool which understands
octrees. It would be a good idea to post messages on OpenDX, Mayavi, VTK
etc...mailing lists asking about support for octrees. I did that and
got little feed back, but more messages would show the developers of these
projects that there is a desire for such a feature.
GfsView makes the most of the octree structure to accelerate
visualisation, computation of isosurfaces etc...
Is there any way to output U, V, W, P, etc...at point (X, Y, Z) in the flow field?
GfsOutputLocation { step = 1 } data -0.209371 -0.0166124 -0.449834
where the last three numbers are the x, y, z
GfsOutputLocation { step = 1 } data positions
where positions is a file containing newline-separated coordinates.
Where is the description of the format of the data
section of saved simulation files?
GfsOutputSimulation { step = 0.1 } sim-%3.1f { variables = P,C }
in this case, the simulations files (sim-0.1, sim-0.2 etc...) will
only contain the P and C variables.
How do I compute/display the vorticity field with OpenDX?
The GfsOutputSimulation and GfsOutputLocation files only place up
to eight decimals. Is there any way to increase the number of decimal places?
I would like a time-averaged velocity profile,
Would I have to specify a number of monitoring points at different heights,
or is there a method to time average over a line through the solution
domain?
EventSum { start = 1 istep = 1 } U SUx
EventSum { start = 1 istep = 1 } V SUy
EventSum { start = 1 istep = 1 } W SUz
EventSum { start = 1 istep = 1 } U*U SU2x
EventSum { start = 1 istep = 1 } V*V SU2y
EventSum { start = 1 istep = 1 } W*W SU2z
OutputSimulation { start = end } simulation-sum {
variables = SUx,SUy,SUz,SU2x,SU2y,SU2z
}
which would add U to SUx at every timestep (istep = 1) starting from
time 1 (start = 1) etc...and U*U to SU2x at every timestep
etc...The resulting sums are then written at the end of the
simulation in the file simulation-sum. This file can then be
post-processed (using gfs2oogl for example) to obtain averages,
standard deviations etc...(along any curves you want of course).
Using animate, the sequence of images generated by OutputPPM looks weird, what's happening?
OutputPPM { step = 0.05 } tracer.ppm { v = T maxlevel = 6 }
which will result in PPM images of size
64 x 64
Why create a new visualisation tool like
GfsView? Can't you use existing tools like Mayavi/VTK, OpenDX etc...?
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