Hi I have a quad-core q6600 64bit (Intel 2.4 GHz), how can I work with all processors at 100% for running simulation in Fluent? Is there some difference for a 64 bit?

Thanks

If you have a parallel license for Fluent you could try for example the command:

fluent 2ddp -t4

in this way Fluent will use your four processors. What operating system you use ?

You need the 64-bit version of fluent and you will also have to run in parallel. The user guide talks about running parallel--you would use the -t4 option when you start fluent from command line although you can also do it through the GUI. Incidentally, this also means you need 4 fluent licenses (which is stupid, but that's the way it is).

i hv pentium D ..it has two cores .... what should be the command?

fluent version -t2 This will start two fluent nodes on your machine, one on each core. It also requires two licenses.