Oh nothing is ever trivial with this much energy around that's for sure.I do
wonder though what the "atmospheric" pressure would be in the middle of the
whole engine cluster while sitting on the pad. Given all the exhausts around it
forming basically a shield I imagine there must be a healthy pressure gradient
from atmospheric to something greater towards the middle.Of course there would
also be an "eudiction" effect along the plume boundary acting to pump it down
too. I think Mr Carmack experienced something along those lines on his hover
tests years ago when the nozzle of his hopper got close enough to the ground to
form effectively a second nozzle or something along those lines?I still like
the spike shaped diverter though, worst case it's failure modes are photogenic
;-)Sent from my Galaxy
-------- Original message --------From: Henry Spencer <hspencer@xxxxxxxxxxxxx>
Date: 22/4/23 1:58 am (GMT+10:00) To: Arocket List <arocket@xxxxxxxxxxxxx>
Subject: [AR] Re: starship pad flame trench? On Fri, 21 Apr 2023, Jake Anderson
wrote:> I want to see a "reverse aerospike" as the diverter.> OK so it's just a
plain spike, with a water outlet at the top, dump a > squillion tonnes of water
out the top of an 8ish meter high spike (to > fit under the OLM) that has a
nice radiused curve into being level with > the ground.Careful here -- the
aerodynamics of flame deflectors, especially big ones, aren't simple. That
exhaust flow is highly supersonic, and when it hits something shock waves will
form, so just making the shape any old smooth curve won't necessarily do what
you want.Henry