[ngj_22]

Hi,

I have questions about some hardware for simulating turbulent flow (LES) with Fluent 12.1.

We are thinking of buying a 24 core computer (4 x Intel Xeon E7530 6C/12T 1.86 GHz 12Mb processors) with 64 GB RAM and 8x300 GB Hard Disk.

We got an offer for the computer with a lot of technical data and as I’m not very technical person I have difficult to see if there will be some problems running Fluent by parallel computing using all 24 CPUs? (If we have the ANSYS HPC license).

We also want to run on a Linux platform and I can see that the computer is certified for Novell SUSE Linux Enterprise Server 10 SP3 (x86_64) and [XEN] (x86_64) and also for Red Hat Enterprise Linux 5.5 (x86_64) and [XEN] (x86_64). Are these Linux versions expensive or are there other free versions you can use if they are supported by the computer?

Can anyone give me suggestions if the hardware is ok for LES simulations and which considerations I need to do before buying the computer? And if I can run Fluent 12.1 on these Linux versions?

Thanks
Nina

[andyj]

p { margin-bottom: 0.08in; }a:link { } I would determine what software you intend to use first. It is difficult for users to change from one complex program to another. You can do that with Word vs Open Office, but not as easily with FEM, CAD and other complex applications. If possible go with what the primary users of the software already know. It sounds like they know Fluent and Ansys.

There are also free open source equivilents available. OpenFoam, Elmer, Salome Mesa, Code Astrid ect..
Next you need to determine what your software license cost will be. Some companies charge per cpu core. Some charge per single computer. If it is going to be on a network that may impact licensing costs. You may have a Server license as well as cliient licenses.Installing on Linux may count as another install.

Some software licences cost $2500 per core. I am unsure about Ansys cost. I do not use Ansys or Fluent. Both are well respected.



Linux is different than Windows. It is a major task to add drivers for video cards and network devices. You may have to build a driver from a raw generic linux file to fit your version of Linux packaging. Easy for an advanced user to do though.


Linux is also more difficult to install. Rather than read a 1,000 page technical manual on the Linux version you are going to run, you might consider hiring a Linux expert to install and configure the software. If you were just going to install Linux in a consumer situation to browse the net and do word processing, no expert would be needed, but to install complicated CAD, CAE and CFD programs, a little Linux expert help may be needed, at a minimum have the correct books on hand and pre-read before starting. Have all the prerequsite software installed that the CFD,CAE or Cad program needs before installing. Correctly configure paths to the package dependencies if needed.
But you can do it yourself with the proper documentation (books..Operating System documentation) . Read the documentation before you start to install. It is best to buy a book on the Linux version you are going to use, as the documentation that comes with the Linux version may not be user friendly, and intended for software engineers and computer scientist.


To dual boot windows and Linux is somewhat difficult, but easy if you have a book and online instructions. I dual boot and it works fine. You can also buy a special hard drive switch to allow hard drives to be powered off if you are not going to be using a hard drive.

Ubuntu Server is pretty much plug and play and free, Red Hat is well developed, respected and mostly free, OpenSuse is mostly free and well developed and also sophisticated Can install openSuse with windows by default.. Centos is the free version of Red Hat enterprise. Scientiific Linux is free and derived from Red Hat Enterprise.. Debian is well developed and free. You usually just buy Linux support. If you do not need the support, then its free.
Make sure you have a compatible network card on hand for install, so you can get updates and drivers. If you do download Linux,do a check sum. Its free to download.

You burn Linux to disk as an iso image, not a regular dvd-cd burn.


Open Source CAE,FEM and CFD article:
www.csc.fi/english/pages/lscfd/Documents/StatusOfFreeSoftwareInCE.pdf


Fluent 12 articles : h50146.www5.hp.com/events/seminars/info/.../0718cae_b2.pdf


https://h30406.www3.hp.com/campaigns/2008/events/.../ANSYS-CFD.pdf


download.microsoft.com/.../ANSYS-MSFT%20HPCS%20Deck_09-17-09.pptx

www.penguincomputing.com/files/whitepapers/FLUENT_Configuration.pdf
cds.comsol.com/access/dl/papers/6429/Pepper_pres.pdf

[andyj]

19th Annual HP Symposium on Technology Trends in Computational Engineering

https://h30406.www3.hp.com/campaigns...sentations.php


https://share.sandia.gov/news/resour...mulation-shows


www.hp.com/.../Multi-coreandFLUENT04AA1-6093ENW.pdf


An Ansys Whitepaper:
www.tynecomp.co.uk/Xansys/Optimal_Performance_ANSYS_11.pdf


The hard drive config may impact performance. RAID may help, as well as loading the OS and Ansys on one RAID drive set ,and loading the data set on another two hard drives in a RAID 0 config. Solid State Drives are an option for the Operating System also, as they are much faster.SSD has improved recently. Front side motherboard bus speeds are an important consideration also. look at the motherboards and hard drive setup as well as the cpu's..Type of memory is also to be considered, look for both speed and bandwidth. Since the computer runs all the time, don't neglect case cooling fans.Monitor the cpu temperatures, and add more (or better) cooling fans if needed .
A 5-8 degree centigrade cpu temperature rise over time implies a layer of cobweb like dust on top of the cpu heatsink, just below the cpu fan.