CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums

Comments

Register Blogs Members List Search Today's Posts Mark Forums Read

  1. Old Comment

    Best Mesh Generation Software

    hi, I will be performing hydrodynamic simulations to assess turbulence in porous obstructions and I will use OpenFOAM as the platform to perform the simulations. What is the best tool (software) to generate the computational grid for OpenFOAM for complicated flow domains? it can be commercial or open source.
    permalink
    Posted March 3, 2015 at 09:28 by saharhad saharhad is offline
  2. Old Comment

    Best Mesh Generation Software

    Quote:
    Originally Posted by aroma View Comment
    I had a study about that. using polyhedral mesh result in faster solution in some cases
    A reply from Simon (post # 2 particularly)

    http://www.cfd-online.com/Forums/ans...l-meshing.html

    It is mentioned there that CFX is already a polyhedra solver by default, but it does not accept poly meshes...

    Fluent can easily handle poly meshes etc...

    There is some advantage of poly meshes in case of high swirl, which CFX automatically gives you, as it is already solving equations on poly meshes...

    But you can not avoid bad quality in narrow gap with the help of poly...

    Poly is inverse of tetra...

    There is no standard method to measure the quality of poly mesh...

    So in short "poly will not be the magic solution to CFD problems"
    permalink
    Posted July 27, 2014 at 15:50 by Far Far is offline
  3. Old Comment

    Best Mesh Generation Software

    I had a study about that. using polyhedral mesh result in faster solution in some cases
    permalink
    Posted July 27, 2014 at 14:54 by aroma aroma is offline
  4. Old Comment

    Best Mesh Generation Software

    Quote:
    Originally Posted by aroma View Comment
    What about star-CCM+? I found that very easy and efficient in polyhedral mesh generation. Have you made any comparison between Fluent poly and Star-CCM+ polyhedral mesh?

    regards
    I have no experience with star-ccm+...

    Never did the comparison between fluent and star ccm+. But i believe there is no need for polyhedra meshes...
    permalink
    Posted July 27, 2014 at 07:29 by Far Far is offline
  5. Old Comment

    Best Mesh Generation Software

    What about star-CCM+? I found that very easy and efficient in polyhedral mesh generation. Have you made any comparison between Fluent poly and Star-CCM+ polyhedral mesh?

    regards
    permalink
    Posted July 27, 2014 at 07:06 by aroma aroma is offline
  6. Old Comment

    Best Mesh Generation Software

    Quote:
    Originally Posted by aroma View Comment
    what about polyhedral mesh?
    You can convert mesh to poly in Fluent ...
    permalink
    Posted July 26, 2014 at 06:11 by Far Far is offline
  7. Old Comment

    Best Mesh Generation Software

    what about polyhedral mesh?
    permalink
    Posted July 26, 2014 at 02:09 by aroma aroma is offline
  8. Old Comment

    Radial Turbomachinery meshing in ICEM

    no specific tut with icem cfd. But you can do it easily in turbogrid.
    permalink
    Posted April 30, 2014 at 05:55 by Far Far is offline
  9. Old Comment

    Radial Turbomachinery meshing in ICEM

    Tutorial for mesh generation of radial compressor by using icem

    Hi Islamabad
    I am new to icem. Now I need to mesh a radial compressor with splitter blades. Could you give me some advice? I will be very appreciated if there is some tutorials related to mesh generation of radial compressor by using icem
    permalink
    Posted April 30, 2014 at 03:03 by dowlee dowlee is offline
  10. Old Comment

    CFX or Fluent for Turbo machinery ?

    Hello Guys,
    I am working on project Flow field analysis through rotor 37 ANSYS CFX. Could anyone please let me know about which turbulence model is better to get results and why ?
    I really appreciate .
    Thanks
    Manpreet Singh
    manpreet_singh_er@yahoo.co.in
    permalink
    Posted March 17, 2014 at 01:22 by manpreet manpreet is offline
  11. Old Comment
    Anna Tian's Avatar

    CFX or Fluent for Turbo machinery ?

    Quote:
    Originally Posted by Far View Comment
    Regarding the comments 2,3 and 4. These problems in Fluent seems to overcome with the new solver technology such as solution steering, pseudo time control, hybrid initialization and better convergence in version 13.
    Now one can get the same solution in one order less iterations (10000--->> 1000 or even less) with few orders more convergence (instead of 1e-02 to 1e-04).
    Even with the linking to design modeler and ansys meshing (ICEM to be included in workbench in release 14.5) through the ANSYS workbench one can easily perform and update the parametric analysis in Fluent.
    Still I feel that the CFX is better than Fluent in turbo machinery (This can be seen from the latest development in turbo machinery modules in CFX 13.) and Fluent in better in external aerodynamics, two phase modeling, combustion and other (all) type of problems.
    CFX has also better option for two-way FSI.
    Embedded LES is another strong feature of Fluent but What I cannot understand why CFX has still not included the embedded rotating reference module which is available in Fluent V 13.0.
    Why Fluent is better in external aerodynamics? Any reason behind that?
    permalink
    Posted December 9, 2013 at 06:52 by Anna Tian Anna Tian is offline
  12. Old Comment

    Accelerating CFD Solutions (Fluent)

    Hi Far,

    Since speeding up solutions has to be done carefully, and since ANSYS published some interesting stuff on the topic of turbulence, here's the link to one of their recent blog posts:
    Quote:
    Everything You Always Wanted to Know About Turbulence Modeling
    http://www.ansys-blog.com/2013/05/20...ence-modeling/
    Best regards,
    Bruno
    permalink
    Posted May 26, 2013 at 10:18 by wyldckat wyldckat is offline
  13. Old Comment

    Best Mesh Generation Software

    Hello Far,

    I am using ICEM, but have recently heard about about Gmsh.

    "Gmsh is a 3D finite element grid generator with a build-in CAD engine and post-processor."


    Easy to use according to the people who have used it. I just heard it today so thought it might be useful information for others here. Although i haven't used it.

    One can get the software for free from website below:
    http://geuz.org/gmsh/

    Regards.
    permalink
    Posted January 14, 2013 at 11:15 by Smaras Smaras is offline
    Updated January 14, 2013 at 11:15 by Smaras (forgot to add one line)
  14. Old Comment

    CFX or Fluent for Turbo machinery ?

    CFX vs Fluent

    Asslamuallikum Sir

    Can transient rotor stator interaction approach in CFX model successfully the turbo machinery cascades with different stator and rotor blade counts i.e. with different pitch ratios (for example if the pitch ration is 0.878) with out any bearing on results? OR if fluent sliding mesh option can account for pitch ratios other than 1?
    Normally in literature i found different methods to account for different pitch ratio's

    1) Phase lag boundary conditions
    2) Harmonic balance methods
    3) Domain Scaling

    I haven't found these methods in Fluent and CFX. May be we have to write UDF's which for the first 2 methods which is an uphill task. And Domain scaling...if someone don't want to use it, what should he do to counter this issue?

    I was doing fan simulation, CFX and fluent pressure based solver didn't work because they were not inducing the flow from rotating to stationary domain due to unknown reasons. When i used the density based solver it worked in the first go and the results were closer to experimental results.

    And Sir, you are right on fluent convergence issues, fluent has some very useful futures as domain reordering, mesh replacing, adaption and repair etc
    permalink
    Posted September 14, 2012 at 14:54 by imran9697 imran9697 is offline
  15. Old Comment

    CFX or Fluent for Turbo machinery ?

    Even better convergence - Fluent 14

    Convergence is much better with Fluent V 14 as compared to V 12. Results of NACA 0012 tutorial from Fluent are compared for Fluent V 12 and V 14. However there is no change in drag and lift coefficients.


    permalink
    Posted February 26, 2012 at 07:18 by Far Far is offline
  16. Old Comment
    permalink
    Posted February 26, 2012 at 04:45 by Fasri.hatomi Fasri.hatomi is offline
  17. Old Comment

    CFX or Fluent for Turbo machinery ?

    Regarding the comments 2,3 and 4. These problems in Fluent seems to overcome with the new solver technology such as solution steering, pseudo time control, hybrid initialization and better convergence in version 13.
    Now one can get the same solution in one order less iterations (10000--->> 1000 or even less) with few orders more convergence (instead of 1e-02 to 1e-04).
    Even with the linking to design modeler and ansys meshing (ICEM to be included in workbench in release 14.5) through the ANSYS workbench one can easily perform and update the parametric analysis in Fluent.
    Still I feel that the CFX is better than Fluent in turbo machinery (This can be seen from the latest development in turbo machinery modules in CFX 13.) and Fluent in better in external aerodynamics, two phase modeling, combustion and other (all) type of problems.
    CFX has also better option for two-way FSI.
    Embedded LES is another strong feature of Fluent but What I cannot understand why CFX has still not included the embedded rotating reference module which is available in Fluent V 13.0.
    permalink
    Posted January 15, 2012 at 10:54 by Far Far is offline
    Updated January 15, 2012 at 23:40 by Far

All times are GMT -4. The time now is 13:20.