(Gary Hudson once said that water injection into the shear layer helps,
but whether "helps" meant 10% or 90% wasn't clear. :-)
The shear layer is where the shorter range high frequencies are generated
but the kinetic energy of the exhaust still has to be dissipated which is
where the low freq. long distance sound is generated. As long as the
engine(s) is/are close to a flame bucket no problem but not portable.
Ken
On Sat, Jan 22, 2022 at 1:07 PM Henry Spencer <hspencer@xxxxxxxxxxxxx>
wrote:
On Sat, 22 Jan 2022, Uwe Klein wrote:
...maybe it could be done -- *without* wings. ... Vertical ascent and
descent is probably *better* for rocket operation from airports.
Just for fun:
overlay the noise footprint of a medium size lifter ( hmm, Ariane, Vega
? ) on some select airport locations.
I suppose in most cases you get a population that is instantly NIMBY
converted. :-)
Seems likely. :-) If it can be done at all, probably it's feasible only
for small vehicles.
Unless somebody can come up with a way to quiet a rocket engine down at
least somewhat... don't know that anybody has seriously explored this.
(Gary Hudson once said that water injection into the shear layer helps,
but whether "helps" meant 10% or 90% wasn't clear. :-) )
Henry
