Steve Higginbotham:
>George, you are a
>rocket guy, so your fluid dynamics is more current than mine is. What
>kind of exhaust profile would you get from an Isp=2,000,000 rocket with
>a 100:1 mouth:throat ratio nozzle? Politely assuming that the nozzle
>shape was optimized for the fluid moving through it, of course...
I'd need to know chamber pressure to work that in detail, which I am
unwilling to do for a fusion rocket. However, rule of thumb is that
the plume will "rapidly" expand until it's internal pressure is equal
to outside atmospheric pressure, and will extend very roughly for
Isp * (Isp/33)^0.5 meters long, which gives us... [nevermind,
the fomula breaks down at these Isp values...]
"A LONG DISTANCE"
I'm more worried about the cosmic ray radiation than the plume, though.
Fluid Mechanics breaks down at relatavistic speeds. "A Reynolds number
of WHAT?????" 8-)
- -george