reentry cavitator

(Henry Spencer) wrote:

In article ,
Derek Lyons wrote:
Agreed 100%. I was merely pointing out that Henry's assertion that
such an effect (using shock waves to form a supercavitating effect) is
impossible is completely wrong.

As Andrew has pointed out, while there is some superficial similarity,
what you get in air is not actually analogous to supercavitation in water.

Have both you and Andrew lost the ability to cogitate?

*I never said that cavitation and shockwaves are analogous phenomena*.

I said the gross *effects* of the two phenomena are the same.

D.
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(Gordon D. Pusch) wrote:
Henry's point (and mine) was that the physics of shock-wave phenomena
have ABSOLUTELY NOTHING IN COMMON with "cavitation."

A very nice point, however, one that has nothing to do with anything
I've written.

You and Henry keep claiming that the shockwave drag reduction effect
cannot be true, because shockwave and cavitation come from different
physical causes. This claim is a falsehood.

I've never claimed that they have anything in common other than
potential uses of their gross effects. The same as a water rocket is
the same as a Saturn V, "for each and every reaction, there is an
opposite reaction".

Moreover, they have opposite effects on the relevant projectile.

One suspects you are not familiar with the Skvall design, cavitation
occurs forward of the main body of the projectile because of a spike
on the nose.

So let's examine the relevance of the physical position of the spike;
Skvall cavitation spike = Nose of torpedo (I.E. pointed into the
flow). Trident -I/-II shockwave spike = Nose of missile (I.E. pointed
into the flow). Proposed re-entry shockwave spike = Nose or tail
depending on exact design (but always, always, *pointed into the
flow*). Therefore, the physical position of the spike (nose or tail)
is irrelevant, so long as it's located on the extremity of the vehicle
that faces into the direction of flow.

One suspects you need to do more thinking and less knee-jerking.

D.
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The STS-107 Columbia Loss FAQ can be found
at the following URLs:

Text-Only Version:
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Corrections, comments, and additions should be
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