Subsonic-Supersonic Supersonic-?

[H_man]

Subsonic-Supersonic... Supersonic--?

Hi all,

I was just wondering.. in the case of the Laval nozzle you go from subsonic to supersonic. But once your flow is already supersonic is there any sense in having a physical nozzle (as surely there is still some divergence to the exhaust) or would it just impede flow? I am thinking about use above the atmosphere.

Cheers,

Harry

 

[russ_watters]

The flow continues to expand and accelerate, guided by the nozzle. There is an optimal nozzle length, though, and some nozzles are actually extendable: http://www.braeunig.us/space/sup1.htm

 

[H_man]

Thanks, that's a great website.

I now see you need different nozzles for different missions depending on the altitude.