Expansion of air

[Becca]

I am currently studying lightning and the energy transfer which goes with it. I am working on the expansion of the air due to the heating caused by the passage of a stroke of lightning through the air. How fast does a column of an ideal gas expand under known temperature increase?

 

I hope someone can help as I seem to be out of ideas.

 

Becca

[UncleAl]

How fast? Blast a gigawatt lightning bolt (milliseconds; 10^5 amps, 10^8 volts, not simultaneously) through the atmosphere and ambient temp molecular gas flashes to plasma (microseconds at most) then detonates outward at multiple machs. The shockwave rapidly decays into a sonic explosion.

 

Lightning

[modest]

This is a good question. The answer would certainly be in fluid dynamics. Have you looked at the Navier-Stokes hydrodynamic equation of a compressible fluid... or perhaps the Euler equation?

 

-modest

[DFINITLYDISTRUBD]

From 0 Deg.C volume increases by 1/273 per degree of temperature.

 

For example- an increase of 1 Deg. would yield a volume of 274/273 of the volume at 0 Deg.

 

Based on Gay-Lussac'sCharle's Law it would the be temperature increase times 1/273 divided by the time the temperature took to increase which should yield the expansion rate in whatever unit of time you use. To just get the overall expansion skip the division. [borrowed and modified from- Practical Mathematics Volume 3 Applied Mathematics-Theory and Practice with Applications to Industrial, Business, and Military Problems- Wm. H. Wise&Co.Inc. C.1951]

 

Hope it helps.

[DFINITLYDISTRUBD]

WOW! Now thats wierd! Two posts both #4

[koji8123]

What type of expanding? Explosions? shock waves?

[DFINITLYDISTRUBD]

What type of expanding? Explosions? shock waves?

 

I am currently studying lightning and the energy transfer which goes with it. I am working on the expansion of the air due to the heating caused by the passage of a stroke of lightning through the air

<-that:)