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Ссылки на открытые коды Cfd


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Предлагаю обмениваться ссылками на открытые коды CFD.

Вот одна из них:

<noindex>http://www.opencfd.co.uk/openfoam/</noindex>

Еще одна ссылка:

<noindex>http://www.llnl.gov/casc/Overture/</noindex>

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  • 3 недели спустя...
Экспериментатор

Насчет ссылок: <noindex>http://www.cfd-online.com/Links/soft.html</noindex>

(нашел в google за минуту поиска)

Но, по-моему, более правильно сообщать ссылки лишь на тот софт которым ты пользовался, и соответственно давать свое мнение по поводу этого продукта.

Меня вот сильно заинтересовал OpenFOAM. Насколько я понял в настоящее время это один из самых мощных открытых CFD пакетов. Так что если кто-то пользовался этим пакетом, черкните хоть пару строк об оставшихся впечатлениях от него.

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  • 9 лет спустя...
Еще одна ссылка: http://www.llnl.gov/casc/Overture/

По ссылке лежит довольно свежий софт - v26 датируется 2015 годом. В том числе есть отссылки на публикации аж 2016-го, что не может не радовать. Однако ранее ничего о нём не знал. Накидаю ссылок от кодера CalculiXForWin

14) http://reef3d.wordpress.com/


З.Ы. Что рабочее, а что нет - абсолютно не в курсе... OpenFOAM, понятно, всем известен

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Так что если кто-то пользовался этим пакетом, черкните хоть пару строк об оставшихся впечатлениях от него.

 

 

+

 

Доступен в исходниках

Много разных решателей на всякие случаи жизни (кроме моего :smile:  )

В общем и целом довольно прозрачный синтаксис описания кейсов

Самое большое коммунити из OpenSource CFD пакетов

Куча конвертеров из разных мешеров (хотя есть и свой)

 

-

 

Решалки тормозные и падучие  :smile:  (хотя конечно все познается в сравнении)

Синтаксис и дизайн исходников ужасен :wallbash:

Странная политика коммитов  в результате которой образовался проект сторонних форков http://www.extend-project.de/

 

Короче штучка для исследователей у которых есть время разбираться в магабайтах исходников сомнительного качества. Инженерам я бы его не порекомендовал бы.

Изменено пользователем HFL
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В свое время пытался провести в OpenFOAM расчет эжекции низконапорного газа в поток нефти с помощью twoPhaseEulerFoam (изотермическая несжимаемая турбулентная дфухфазка). Геометрия была осесимметричная с зоной сужения. Уперся в разрыв скоростей. Возможно, решатель не был предназначен для сверхзвуковых потоков...

 

Работал под Windows, использовал эти бинарники и препроцессинг в Discretizer, но потом нашел интегрированную SCADA Symscape. В 2010 у них была поддержка только однофазных решателей, сейчас не знаю.

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  • 1 месяц спустя...

В CalculiX 2.10 анонсирована поддержка Навье-Стокса. Ручки дотянутся - потестим =))

 

New features in Version 2.10 of CalculiX (check the documentation!)
  • Procedures
    • ...
    • Compressible laminar flow works (CFD)
    • Introduced parallellization in CFD-Calculations
  • CalculiX GraphiX
    • ...
    • Changed or extended commands:
      • send: The mass-flow in a cfd calculation can be written (mflow).

 

 

*CFD

Keyword type: step

This procedure is used to perform a three-dimensional computational fluid dynamics (CFD) calculation.

There are four optional parameters: STEADY STATE, TIME RESET, TOTAL TIME AT START and COMPRESSIBLE.

The parameter STEADY STATE indicates that only the steady state should be calculated. If this parameter is absent, the calculation is assumed to be time dependent and a transient analysis is performed.

The initial time increment and time step period are interpreted mechanical time increment and mechanical time step. For each mechanical time increment a CFD calculation is performed consisting of several CFD time increments. Therefore, the initial CFD time increment cannot exceed the initial mechanical time increment. CFD time increments are usually much smaller than the mechanical time increments. The CFD calculation is performed up to the end of the mechanical time increment (if the calculation is transient) or up to steady state conditions (if the CFD calculation is a steady state calculation).

The parameter TIME RESET can be used to force the total time at the end of the present step to coincide with the total time at the end of the previous step. If there is no previous step the targeted total time is zero. If this parameter is absent the total time at the end of the present step is the total time at the end of the previous step plus the time period of the present step (2nd parameter underneath the *COUPLED TEMPERATURE-DISPLACEMENT keyword). Consequently, if the time at the end of the previous step is 10. and the present time period is 1., the total time at the end of the present step is 11. If the TIME RESET parameter is used, the total time at the beginning of the present step is 9. and at the end of the present step it will be 10. This is sometimes useful if transient coupled temperature-displacement calculations are preceded by a stationary heat transfer step to reach steady state conditions at the start of the transient coupled temperature-displacement calculations. Using the TIME RESET parameter in the stationary step (the first step in the calculation) will lead to a zero total time at the start of the subsequent instationary step.

The parameter TOTAL TIME AT START can be used to set the total time at the start of the step to a specific value.

Finally, the parameter COMPRESSIBLE specifies that the fluid is compressible. Default is incompressible.

 

First line:

  • *CFD
  • Enter any needed parameters and their values.
  • Initial time increment. This value will be modified due to automatic incrementation, unless the parameter DIRECT was specified (default 1.).
  • Time period of the step (default 1.).
  • Minimum time increment allowed. Only active if DIRECT is not specified. Default is the initial time increment or 1.e-5 times the time period of the step, whichever is smaller.
  • Maximum time increment allowed. Only active if DIRECT is not specified. Default is 1.e+30.
  • Initial time increment for CFD applications (default 1.e-2). If left free, a proper initial increment is calculated.

Example: couette1

*CFD.1,1.,,,0.01

defines a CFD step. The second line indicates that the initial time increment is .1, the total step time is 1 and the CFD time increment is 0.01.

 

Example files: thermomech.

Изменено пользователем AlexKaz
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насколько я понял, там сейчас только ламинарное течение сделали

 

Кстати, вопрос. А задачи акустики в нем не решали?

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В группе на канале yahoo нашёл 2 топика по теме acoustic. Сам не решал, в хэлпе должен быть пример и теория.

 


Acoustic normal modes
Expand Messages

Paul Howes
Message 1 of 2 , Feb 9, 2009
I am a physics lecturer in the UK and for the last couple of years have
run an undergraduate project in which the students model the normal
modes of a metal bar (vibraphone bar) using Calculix. The aim is for the
students to design a bar that has normal frequencies that are
harmonically related so that it sounds a distinct musical tone when
struck. In the second part of the project our mechanical workshop makes
a bar to the students' design so that they can measure the normal
frequencies and compare the result with their predictions from FEA. The
students run Calculix on an old PC. They parameterize the bar shape and
call scripts to automatically mesh the model (gmsh or netgen) and find
the frequencies (ccx). It has been a popular project that has engaged
the students interest.

This year I am hoping to get the students to model a drum with varying
membrane thickness. I think that for such a thin membrane the inertia of
the air will be important. This is particularly true if the drum body
creates a closed volume (such as timpani). I only want to calculate the
normal frequencies of the drum membrane and air (and maybe the drum
body), not the time response of the drum after being struck. I have read
the Acoustics page of the manual but it is still not entirely clear to
me whether Calculix can do what I want. It is also not clear to me how
to go about writing the .inp file for such a calculation.

Any help would be greatly appreciated.

Thanks to Guido for making such an excellent program available.

Paul Howes.
--
Paul Howes
Reply
guido dhondt
Message 2 of 2 , Feb 10, 2009
Hi Paul,

it is nice to hear that you are using CalculiX for your lectures!

Concerning your question about the eigenfrequencies of a drum: it is quite
easy to calculate the eigenfrequencies of an elastic body and the same
applies to those of a volume of air (for instance for a flute etc.). The
connection of both, though, is much more difficult. Right now, it is not
possible to perform a frequency calculation for a combination of air and
elastic body. The only solution I can offer you is to perform a dynamic
calculation due to a harmonic excitation with increasing frequency (something
like sin(t**2)). The resonant frequencies pop up as singularities in the
resulting response.

In order to do a combined *DYNAMIC calculation for the drum I would have to
extend the interface for the user function dflux.f. The idea is the
following: you create a separate mesh for the air and the elastic body. The
elastic body is loaded by the air pressure, which is the primary variable of
an acoustic calcultion, the air is loaded by the accelaration of the elastic
body (cf. the analogy of the variables in the acoustic section). So far, the
acceleration is not available in the dflux interface, I would have to change
that. Furthermore, you would have to write a dload.f and dflux.f user
routine. Depending on your time schedule, I could offer to do that for you.

The only further limitation is that I have to provided for the second
derivative w.r.t. time of the acoustic equation in a *DYNAMIC calculation (
the heat transfer counterpart is a first derivative w.r.t.time). This means
that you would have to discard the inertia of the air, i.e. it is assumed
that the air reacts instantaneously to accelerations of the elastic body.

I propose that you investigate first whether a frequency sweep (dynamic
calculation with increasing frequency) suits you, for instance you could try
on a beam or whatever other structure. If this works, please tell me if you
would like me to write the user subroutines for you.

I have been practicing on congas the last couple of years, this would also be
a nice application.

Best Greetings,

Guido

Am Montag, 9. Februar 2009 11:28:50 schrieb Paul Howes:

Show message history

 

Message 1 of 9 , Sep 22, 2010

1 Attachment 68 KB

ideal_gas.tar.bz2

Hi all,

somebody asked for acoustic calculations. I coded a material for an ideal gas.
Please find attached the FORTRAN files to be exchanged and an example. The
gas is modeled as an isotropic material with 0 shear modulus and a Lambda
Lame constant equal to rho*specific gas constant*temperature in Kelvin.

Best Greetings,

Guido

 

 

  • iskandhar2000
    Sep 24, 2010
    --- In calculix@yahoogroups.com, guido dhondt <dhondt@...> wrote:

     

    Hi Guido

    How do I include the material definition to be used by ccx solver...?

    Do I have to recompile ccx, and include umat_ideal_gas. and umat_main in the makefile...?

    BRGDS

    Alex

    Reply
  • guido dhondt
    Sep 28, 2010
    Hi Alex,

    in the meantime I found a better solution, you do not need a user routine.
    Since the material is linear you can define it by using the *ELASTIC keyword.
    Air can be modeled as a linear elastic material with shear coefficient zero
    and first Lambda Lame constant = density * r * Temperature in Kelvin. In SI
    units density = 1 and r=287 J/kgK. So for 1000 K you have the following
    coefficients:

    *ELASTIC,TYPE=ORTHOTROPIC
    287000.,287000.,287000.,287000.,287000.,287000.,0.,0.,
    0.,1000.

    I tried a *DYNAMIC calculation, this works. If you do a *FREQUENCY calculation
    you may have to put the shear modulus to 287000 (or some similar number) as
    well in order to get reasonable frequencies.

    Hope this helps,

    Guido

    Am Freitag, 24. September 2010 17:04:55 schrieb iskandhar2000:
    Show message history

    Reply
  • Rovera Alessandro
    Sep 29, 2010
    Hi all,
     
    I have an axial symmetric model discretized with a mix of cax6 anc cax8r elements.
    When I try computation I return the following errors:
     
    many...
     
     *WARNING in e_c3d: nonpositive jacobian
              determinant in element 4834
    ecc...
     
    But I have verified, the mesh is quite good, and in my model the minimum jacobian is 0.57
    What is happen?
     
    Reply
  • Jason Nicholson
    Sep 29, 2010
    Did you create the mesh with CGX?  Did you check it with CGX?  If you exported from a different program, the node numbering could be different causing invalid elements. 

    Sincerely,
    Jason Nicholson

    Show message history

    Reply
  • Rovera Alessandro
    Sep 29, 2010
    thanks for your repley JAson.
    I have found the problem! I sketch my model in x-y plane but in negative x value.
    After reflect the model about y axis the problem on negative jacobia dissapear.
    I have checked on CalculiX manual, but this fact is not right enphatized.
     
     
    Alex
     
     
    Show message history

    Reply
  • Rovera Alessandro
    Sep 29, 2010
    Hi all,
     
    is it possible to use contact in axial-symmetric computation?
    And if yes how? Slave node-set againts master edge element-set?
     
    Alex
     
    Show message history

    Reply
  • john_platko
    Oct 1, 2010
    Guido,

    Thanks for posting this. I too was looking for a way to model air.

    Regards,

    John

    Show message history

    Reply
  • Jeff Baylor
    Message 9 of 9 , Oct 27, 2010

    I have an axi-symmetric model with contact and large deformations that I solved using CCX 1.8.  The results agreed well with some experimental data, so I am happy with them.  There was a change in the solution when I solved it with 2.0, but have not gone back and checked against 2.1 or 2.2 yet.  I am going to be revisiting the problem in the next few weeks, so I will let you know the new solver gives the same answers as I saw in 1.8.

     

     

    Jeff Baylor
    -----------------------------------
    Convergent Mechanical Solutions LLC
    web:   http://bConverged.com
    email: jbaylor@...
    phone: 206.755.6199

     

     

     

    From: calculix@yahoogroups.com [mailto: calculix@yahoogroups.com ] On Behalf Of Rovera Alessandro
    Sent: Wednesday, September 29, 2010 8:02 AM
    To: calculix@yahoogroups.com
    Subject: [calculix] axial symmetric model

     

     

    Hi all,

     

    is it possible to use contact in axial-symmetric computation?

    And if yes how? Slave node-set againts master edge element-set?

     

    Alex

     

ideal_gas.tar.bz2.zip

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  • 4 месяца спустя...
В CalculiX 2.10 анонсирована поддержка Навье-Стокса. Ручки дотянутся - потестим =))

В тот раз ни один из примеров с жидкостью у меня не заработал. CFD похоже был не допилен. Но Гвидо таки не унывает, 31 июля запилил версию 2.11.

 

New features in Version 2.11 of CalculiX (check the documentation!)
  • Procedures
    • Rotational and translational cyclic symmetry for CFD was coded (see examples couette1per, couettecyl4 and couettecyl4comp).
    • Sensitivity analyses (cf. Section 6.9.22 in the User's Manual)
    • Speed-up of the treatment of SPC's and MPC's in the stiffness and mass matrix.
  • Elements
    • Box, U and L-section beams were coded (Section 6.3.2. in the User's Manual; special thanks to Prof. Otto Bernhardi of the Karlruhe University of Applied Sciences for doing this).
  • Documentation
    • Expanded the documentation on gas networks.
  • CalculiX GraphiX
    • Changed menu function: In the previous versions of cgx the "vMises" strain was calculated with the same algorithm as used for the vMises stress. This is now corrected to vMises_strain=2./3.*stressAlgorithm
    • Changed or extended commands:
      • elty: be2f,be3f elements for fluid networks (ccx: *ELEMENT,TYPE=D).
      • send: parameter 'cr' for cavity radiation conditions with uniform emissivity and sink temperature or sink node is available.
    • New commands:
      • fil: Command line version of qfil.
      • grpa: Assigns a group number to certain elements stored in a certain set. The group number is an element attribute used in the frd file.
      • int: Command line version of qint. 
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  • 9 месяцев спустя...

OpenFOAM пытаются скрестить с FreeCAD, сейчас код глючит.

Цитата

* Incompressible, laminar flow (simpleFoam).
* Basic material data base.
* Flow initialisation with a potential solver.
* Tetrahedral meshing using GMSH including multiregion meshing (using FEM workbench functionality).
* Post processing using paraview.
* Porous regions and porous baffles.
* Runs on Windows 7-10 (https://opensimsa.github.io/download.html, see CFD)
* Unit testing

Planned developments for 2017:

* Cut-cell Cartesian meshing with boundary layers.
* Extension to turbulent using RANS (k-w SST).
* Conjugate heat transfer.

We have created step-by-step training material for the workbench at https://opensimsa.github.io/training.html

Any comments and feedback will be appreciated.

cfdWb.png

https://forum.freecadweb.org/viewtopic.php?f=18&t=21576

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