Hi, I have a problem when I use FLUENT5.3. I want to change two symmetry boundary conditions to a couple periodic boundary condition. However, I can not find this MENU in Flunet5. Could you tell me how to change them? Has FLUENT5 this function?

You mast use the command line with these istructions:
:define
:bc
:modify-zone
:make-periodic

then answer the questions. By.

Could you tell me some details?

1. i've a problem using fluent 5.1. i want to model 1 full mixing tank, but because it's difficult to mesh full tank, i draw 1/4 tank and then copy and rotate it in TGRID, and merge the zone i want. everything is ok in TGRID, but after i imported to fluent, fluent separate the zone. then i try use TFILTER. it's fine, but after i imported that mesh file to fluent again and using merge zone, theres a message unable to merge thread. zone X and Y doesn't match. What wrong with that????(i think i can merge any zone without restrictions).

2. can u tell me, how to add a new boundary cond type of Discrete Phase Modelling (escape,trap,reflect). i want to make myself.

maybe i can tell you the other way. you can back to your gambit. if you've mesh your volume, remove mesh first and then click link mesh, on mesh surface. click surface to be linked and point of linking. then gambit will draw a vector on the edge of your surface. then click adjacent surface (shadow surface), click the point of the 2nd surface, and then a point. if direction of the vector isn't same, click reverse. then you can mesh your volume. (see Fluent volume 1 on periodic boundary condition f or detail)