GGDT problem?

[Copperboy]

I've recently downloaded the GGDT. And I must say it's a hell of a program!
But I just wonder, when I type in measures in the box of the outer diam. for reservoir data, the volume changes
Shouldn't the volume ONLY be defined by the INNER diam???
Have i got something wrong here

[boilingleadbath]

Yeah, read the documentation.
The diameters of the chamber define the air volume in it; the outside is the interior of the pipe, and the interior cavity is there for if you have a cylindrical object in your chamber. (such as a barrel in a co-axial design)

...I bet you'll be pleasently surprised when you do this and notice that your velocities are much higher.

[Copperboy]

Thanks Alot! That's a pretty smart feature I gotta admit...when you know about it!