/sci/ - Science & Math

>>6408394
the science you start with (rocket equation, etc.) is in basic physics textbooks. start there.

good links here: http://psas.pdx.edu/RocketScience/

Good evening, /sci/ (it's always evening where it's classy). I'm yet another undecided college student, and I, like many other people who ended up going into STEM, "liked math in high school". The problem is, I do not know which scientific/mathematical field requires what type of thinking. I always enjoyed solving problems at competitions and all my math classes, and I like programming (but only for the problem-solving aspect of it). People who are good at math go into some engineering fields, or maybe pure/applied math, or the sciences, etc. But if all of those people are "good" at math, then what would make one choose physics over electrical engineering, for example?

Sorry if this sounds a bit obtuse, I might be stupid so I can't formulate a direct and simple question.

Thanks for any input, and please don't sperg over this.

pic semirelated, random one i just found.

I'm coming across a lot of good stills in my folder... anyone object to this becoming just a general engineering-related media thread?

>>4162307
>I've slipped up somewhere.
Yes, in thinking that you have the expertise to engineer this thing from the ground up.

Do yourself a favor, swallow your pride and go follow someone else's work until you can reproduce a working rocket engine. Once you've gotten to that point, THEN you can start thinking about designing your own shit.

http://www.jamesyawn.net/modelrocket/index.html

http://www.nakka-rocketry.net/

Now, while I'm quite certain you won't be achieving orbit, I DO want you to at least achieve some level of success, and I AM more than happy to help you, but you HAVE to believe me when I tell you that you are getting WAY ahead of yourself right now. A few initial flaws I see with your design already:
>Extremely poor nozzle design (WAAAAY overexpanded and WILL suffer from detached flow)
>Casing is extrmely heavy (not a fatal flaw by any measure if your only intent is static tests)
>Compacted powder propellant is unpredictable and has mechanical properties that are unacceptable for larger motors
>You're looking at ENERGY instead of IMPULSE for a ROCKET MOTOR (I mean, seriously, dude. SERIOUSLY.)
You really ought to back up to square-one at this point; you haven't lost too much yet to get off on the right foot. Plenty of others have blazed this trail before, and fiddling around for weeks/months trying to rediscover these simple fundamentals is only a waste of your time.

Okay... momentum flux integrated through nozzle area will give you impulse per unit time = force. Of course, the amount of impulse needed to arrest the descent can be determined from the (under-parachute) descent RATE (presuming it is provided), mass of the vehicle, gravity, and duration of your burn.

I'm not sure how atmospheric pressure plays into this yet, you'll have to explain further to illustrate how it matters. Are you actually looking at the effect of back-pressure on a C-D nozzle? Are you using a simplified (incompressible-flow, Bernoulli) model for the thruster? Is this a fluids course?

So /sci/, highschoolfag here. I know that when i go into college it will most likely be a tech school and i will do something science related. I'm not sure if I should do engineering (I can't even figure out which type would suit me best), physics (I have always been fascinated and wanted to work at CERN or something), or computer science (since im an introvert who likes to solver problems and deal with algorithms/logic).

Can anyone in such fields of study offer any input?

Why does a nozzle decrease velocity for subsonic flow, but increase it for supersonic flow?