Search Results

User Name Remember Me Password

Showing results 1 to 22 of 22 Search took 0.00 seconds. Search: Posts Made By: RodriguezFatz

Forum: Main CFD Forum March 11, 2014, 07:26

Replies: 52 LES evaluation help needed Views: 4,704 Posted By RodriguezFatz This sounds perfect. Sorry aqua I am too buisy... This sounds perfect. Sorry aqua I am too buisy and had such short comments only!

Forum: Main CFD Forum March 11, 2014, 06:49

Replies: 52 LES evaluation help needed Views: 4,704 Posted By RodriguezFatz Ok, if they vary strongly then you are doomed.... Ok, if they vary strongly then you are doomed. Maybe you can create a custom function in Fluent? Is dx and dz available in Fluent?

Forum: Main CFD Forum March 11, 2014, 06:44

Replies: 52 LES evaluation help needed Views: 4,704 Posted By RodriguezFatz Then you just need to go to the relevant edge... Then you just need to go to the relevant edge (parallel to the surface) and read the sizing of the cells.

Forum: Main CFD Forum March 11, 2014, 06:40

Replies: 52 LES evaluation help needed Views: 4,704 Posted By RodriguezFatz Do you use blocking/hexa for meshing? Do you use blocking/hexa for meshing?

Forum: Main CFD Forum March 11, 2014, 06:34

Replies: 52 LES evaluation help needed Views: 4,704 Posted By RodriguezFatz Sorry, I don't know anything about Starccm, maybe... Sorry, I don't know anything about Starccm, maybe people in the sub-forum can help you...

Forum: Main CFD Forum March 11, 2014, 06:31

Replies: 52 LES evaluation help needed Views: 4,704 Posted By RodriguezFatz Ok... I get them from ICEM. What do you use for... Ok... I get them from ICEM. What do you use for meshing?

Forum: Main CFD Forum March 11, 2014, 06:17

Replies: 52 LES evaluation help needed Views: 4,704 Posted By RodriguezFatz Hi, What I do is just calculating x+ =... Hi, What I do is just calculating x+ = (y+ / dy) * dx with dy and dx the real physical coordinates.

Forum: Main CFD Forum March 10, 2014, 09:50

Replies: 52 LES evaluation help needed Views: 4,704 Posted By RodriguezFatz I use Fluent, and here, you need to evaluate x+... I use Fluent, and here, you need to evaluate x+ and z+ by yourself. "y" is allways the direction of the flow in fluent, even if it isn't actually the "y-direction" of your physical coordinates.

Forum: Main CFD Forum February 15, 2013, 05:21

Replies: 52 LES evaluation help needed Views: 4,704 Posted By RodriguezFatz I guess I did not illustrate my thoughts clear... I guess I did not illustrate my thoughts clear enough: You can run a simulation with LES turbulence model and a bad (too large) grid. Then, the level of modeling of the SGS model will be quite high....

Forum: Main CFD Forum February 15, 2013, 04:40

Replies: 52 LES evaluation help needed Views: 4,704 Posted By RodriguezFatz Well I know how to start a DNS. I ment an advise... Well I know how to start a DNS. I ment an advise how to use this information to judge whether the SGS works fine or not...

Forum: Main CFD Forum February 15, 2013, 04:08

Replies: 52 LES evaluation help needed Views: 4,704 Posted By RodriguezFatz Radial distribution ok, but that only helps for... Radial distribution ok, but that only helps for types of flows where reference values are known. Comparing to DNS results or experiments does only mean you get the correct real results. That does not...

Forum: Main CFD Forum February 15, 2013, 03:49

Replies: 52 LES evaluation help needed Views: 4,704 Posted By RodriguezFatz I see there are different approaches for the time... I see there are different approaches for the time step setting. Thank you for this insight. One additional question: Is there any reasonable way to judge if the LES model works in a somewhat...

Forum: Main CFD Forum February 14, 2013, 07:44

Replies: 52 LES evaluation help needed Views: 4,704 Posted By RodriguezFatz So it's recommened to take the worst case... So it's recommened to take the worst case (=smallest) time step to ensure that it is actually small enough. Ok, but if you double it afterwards and compare the results you can learn for future...

Forum: Main CFD Forum February 14, 2013, 07:00

Replies: 52 LES evaluation help needed Views: 4,704 Posted By RodriguezFatz Sorry, but I still don't get your point. :o ... Sorry, but I still don't get your point. :o Now, there is some time scale needed for DNS. For LES the grid is coarser and the fastes eddies get modeled - so the required time step gets larger. The...

Forum: Main CFD Forum February 14, 2013, 05:07

Replies: 52 LES evaluation help needed Views: 4,704 Posted By RodriguezFatz Of course, but for a given grid I get some... Of course, but for a given grid I get some maximum velocities. Grid-size devided by this velocity gives a time-step estimation. Is this correct? (Courant-number estimation)

Forum: Main CFD Forum February 14, 2013, 04:57

Replies: 52 LES evaluation help needed Views: 4,704 Posted By RodriguezFatz Is this really the relevant time-scale? I don't... Is this really the relevant time-scale? I don't think so, because the needed time-scale should depend on the grid size.

Forum: Main CFD Forum February 14, 2013, 04:51

Replies: 52 LES evaluation help needed Views: 4,704 Posted By RodriguezFatz Alright, that was what I ment. I wanted to change... Alright, that was what I ment. I wanted to change dt just to see, if it is already small enough!

Forum: Main CFD Forum February 14, 2013, 04:44

Replies: 52 LES evaluation help needed Views: 4,704 Posted By RodriguezFatz As I understand it, for a given grid, there... As I understand it, for a given grid, there should be independence of LES statistics for small time step sizes. Thus, when I decrease my time step, hopefully results won't change... Right now I...

Forum: Main CFD Forum February 14, 2013, 04:33

Replies: 52 LES evaluation help needed Views: 4,704 Posted By RodriguezFatz Sorry, I ment, I can double / half the time step... Sorry, I ment, I can double / half the time step size to see if any relevant parameter changes.

Forum: Main CFD Forum February 14, 2013, 04:27

Replies: 52 LES evaluation help needed Views: 4,704 Posted By RodriguezFatz Of course you are right, my bad. But for the time... Of course you are right, my bad. But for the time step size I could do that, right?

Forum: Main CFD Forum February 14, 2013, 04:10

Replies: 52 LES evaluation help needed Views: 4,704 Posted By RodriguezFatz Dear Filippo, thanks for your fast reply. With... Dear Filippo, thanks for your fast reply. With "kinetic energy" you mean the kinetic energy of the resolved scales, right? I have to do this with a custom field function "0.5 * v * v * rho"? All...

Forum: Main CFD Forum February 14, 2013, 03:22

Replies: 52 LES evaluation help needed Views: 4,704 Posted By RodriguezFatz LES evaluation help needed Dear all, I try to get some experience in LES and need some help. My setup is a simple straight pipe of 4m length and 1m diameter. Periodic bc with a mass flow rate of 0.044 kg/s is applied,...

Showing results 1 to 22 of 22

Forum Jump User Control Panel Private Messages Subscriptions Who's Online Search Forums Forums Home General Forums     Main CFD Forum     System Analysis     Structural Mechanics     Electromagnetics     CFD Freelancers     Hardware     Lounge Software User Forums     ANSYS         CFX         FLUENT             Fluent Multiphase             Fluent UDF and Scheme Programming         ANSYS Meshing & Geometry     Autodesk Simulation CFD     AVL FIRE     COMSOL     CONVERGE     Fidelity CFD     FloEFD, FloWorks & FloTHERM     FLOW-3D     OpenFOAM         OpenFOAM News & Announcements             OpenFOAM Announcements from ESI-OpenCFD             OpenFOAM Announcements from OpenFOAM Foundation             OpenFOAM Announcements from Other Sources         OpenFOAM Installation         OpenFOAM Meshing & Mesh Conversion         OpenFOAM Pre-Processing         OpenFOAM Running, Solving & CFD         OpenFOAM Post-Processing         OpenFOAM Programming & Development         OpenFOAM Verification & Validation         OpenFOAM Community Contributions             OpenFOAM CC Toolkits for Fluid-Structure Interaction         OpenFOAM Journal         OpenFOAM Bugs     Phoenics     REEF3D         REEF3D News & Announcements     Siemens         STAR-CCM+         STAR-CD     SU2         SU2 News & Announcements         SU2 Installation         SU2 Shape Design Mesh Generation & Pre-Processing Software     ANSA     enGrid     GridPro     Pointwise & Gridgen Visualization & Post-Processing Software     EnSight     FieldView     ParaView     Tecplot Special Topics     Mesh Generation & Pre-Processing     Visualization & Post-Processing CFD Online Community     Site News & Announcements     Site Help, Feedback & Discussions     CFD-Wiki