/sci/ - Science & Math

when did you first aquire an interest for rocket surgery?

What do you see as the future boosting shit into orbit? Will conventional rockets get replaced? Will they get refined?

Are you aspie?
Do you have ADHD?
Why rocket science?
What's your IQ?

>>2736930
Even when I was very young I was interested in airplanes of all kinds. Doodling pictures of F-16's in combat and such.

On the more adult end, when I read the class list for undergrad aerospace studies, I was hooked.

>>2736933
There simply aren't any viable technologies even on the horizon to replace rockets. All these space elevators, skyhooks, yadda yadda yadda are such pie-in-the-sky ideas, and saying they're 20 years out is kinda nuts.

I see SSTO, or hybrid air-breathing rockets being the best shot for something "new."

>Are you aspie?
No.
>Do you have ADHD?
Oh hell yes.
>Why rocket science?
Cause chicks.
>What's your IQ?
Hasn't been tested in many years. High, but irrelevant.

Hey OP, would you recommend this book as an intro to orbital mechanics and whatnot?

Why did you set your sights so low?

>>2736956
Absolutely, it's on my shelf. I suspect I even recommended it here in the past.

>>2736957
Well, some would say that still being "in school" in your late 20s is pretty low. But, screw em.

>>2736970

>Absolutely, it's on my shelf. I suspect I even recommended it here in the past.

Great. Any others that might come in handy?

What are the best schools for aerospace engineering in Europe?

>>2736978

Cranfield University and the University of Glasgow are two good ones in the UK

>>2736988
I was gonna say Glasgow, TU Delft, ETH Zurich. Apart from that I don't really know, as I'm American.

>>2736976
I have "Spaceflight dynamics" by Wiesel, but I recall thinking it was inferior to that BM&W book while 10 times the cost. Curtis' "Orbital Mechanics" is apparently quite good as well, but I haven't personally used it.

I heard plasma propulsion is relatively weak, so why are they developing it?

>>2737003

I'm at Glasgow doing MSc Aerospace Eng :D

>>2736929
>rocket scientist
so you're an engineer...

>>2737003

Allright!

>>2737009
Not sure if troll? Assuming troll.

>>2737011
Heh, cool. I literally know one person that went there for PhD, but he's now quite famous and smart.

Otherwise, as far as academia (and industry, really) is concerned, Euro universities might as well not exist. There's the occasional useful research in applied math from oxbridge, but beyond that, I dunno.

Could you make a rocket gun? The bullets are rockets, in the barrel they act very much like a bullet with the rocket exhaust acting in the same way as propellant, after they leave they fly at a terminal velocity until they run out of fuel adding significant range.

To keep things simple the rocket gun is a bolt action sniper rifle. Accuracy is an important element of functionality so one question is whether the bullets should be flechete shaped or rocket shaped.

What do you think?

>>2737047

>http://en.wikipedia.org/wiki/Gyrojet

>>2737047
Google "Gyrojet".

THE FUTURE IS DECADES AGO!

>>2737059
>>2737047
http://en.wikipedia.org/wiki/Project_HARP

Is your job incredibly stressful?

Do you have much downtime?

>interesting questions discouraged.
>boring shit encouraged.

well fuck you too, OP.

Do you have any advice for an aerospace engineer struggling with fuck off hard statics shit? Why can I do third-order differentials with no trouble, but I can't wrap my head around fucking vectors and moments?
Though I suppose this isn't your field.

[stupid question] Do you really call yourself a rocket-scientist, or do you use the term astrophysicist or aerospace engineer (if you're an engineer)?

[better question] Do you find you use high DOF numerical solvers often (SVD, preconditioned Jacobi, Krylov space CG, etc), or can you do your work without these? I ask because I'm entering a graduate program working on aeroelasticity, and I don't see much use in learning the algorithms behind MATLAB.

['Nuther question] Do you use algebraic simplifications often? I understand the necessity to only solve specific cases of hard problems (Navier-Stokes), but is this all there is, or does the science move into more "real-world" equations rather than the freshman physics, friction-doesn't-exist world?

>>2737075

Obviously, future Aerospace Engineer.

serious questions:

how is your love-life?
how is your family?

>>2737047
It's called a "recoilless rifle."

>>2737069
>Is your job incredibly stressful?
Well, my job is to do advanced research in a field I really love. So there's stress associated with the challenge and the amount of time put in, but other than that, I enjoy it so it's not too stressful.

>Do you have much downtime?
I'm generally working in my office 10 hours a day, 5 or 6 days a week, and thinking about things otherwise. There's enough downtime for me to get good and drunk pretty regularly.

>>2737109
recoilless implies the barrel is not sealed on it's rear end

I'm an undergrad aero student, 3.69 GPA just finishing up my sophomore year. I've been looking into grad school for aero engineering..

Would you recommend it? Also, how is the workload? I don't plan on pursuing a PhD yet or anything, just a MS

>>2736929

Need some help with stress in thick walled pressure vessels. Can calculate the stress with an internal pressure fine but I don't know what happens when there is an external pressure too.

Can't find anything on google about this. Do I calculate the stresses for each pressure individually then add them to get a resultant stress or is it more complicated?

>>2737075
>Do you have any advice for an aerospace engineer struggling with fuck off hard statics shit? Why can I do third-order differentials with no trouble, but I can't wrap my head around fucking vectors and moments?
>Though I suppose this isn't your field.
That's exactly my field, more or less. Statics: everything sums to zero. That's it. Sum of forces, sum of moments, you're done. If I were your TA I could help you more, but my advice: get that shit down or you'll be in a world of hurt later on. Fluid mechanics without a basic understanding of statics == fucked.

>>2737080
>[stupid question] Do you really call yourself a rocket-scientist, or do you use the term astrophysicist or aerospace engineer (if you're an engineer)?
Aerospace engineer, and I don't even really work in rockets per se, but more in supersonic combustion. Joke title.

>[better question] Do you find you use high DOF numerical solvers often (SVD, preconditioned Jacobi, Krylov space CG, etc), or can you do your work without these? I ask because I'm entering a graduate program working on aeroelasticity, and I don't see much use in learning the algorithms behind MATLAB.
I use them all the time (I do CFD.) I write software to solve these kinds of problems, so I need to know them inside out. Even if you can get by with just using matlab for everything, you should take a course in numerical methods, since different problems will require different methods, and matlab won't tell you which is best.

>['Nuther question] Do you use algebraic simplifications often? I understand the necessity to only solve specific cases of hard problems (Navier-Stokes), but is this all there is, or does the science move into more "real-world" equations rather than the freshman physics, friction-doesn't-exist world?
Well, in CFD, we discretize Navier-Stokes in linear algebraic equations. But we do actually use a lot of simplifications to get ballpark estimates, and know generally what we're looking for in a more detailed simulation. They always provide a reality check, and good first order results.

>>2737117

So, I'm this guy (>>2737080), and as a current Masters' student, I'd like to share my experience. Many schools award masters' on the way to a doctorate, but if you declare a doctoral track, then professors will fund you.

I'm doing a straight masters', and I'm paying for my graduate degree. Pretty much all grad students get some tuition break, but I've seen more and more that only the doctoral students get full rides and stipends.

>>2736954 >Do you have ADHD?
>>2736954 Oh hell yes.

Uhm, any advice for another suspected ADHD twat?

>>2737127

You do CFD? You are a god amongst engineers. After one numerical methods class and one CFD class, I chose a nice project what involves plenty of nasty FEA code, but nasty in the discontinuous and nonlinear way, not in the millions of eigenvalues make you cry way.

>>2737117
Certainly, provided you figure out what specific area in aerospace you like. Just an MS opens lots of doors for employment -- more interesting work, besides a bit higher pay.

As far as workload, I think my junior year of undergrad was probably my most intense -- aerodynamics, orbital mechanics, aircraft design, and something else... I put a lot of hours in then. Grad school can be as hard or as easy as you make it... sometimes I put in as many or more hours as I did back in undergrad, but since I've chosen my direction and I love all my courses and research, it's not a chore; it's a labor of love.

>>2737133
Yeah, pretty much this. Although I got tuition break, and an assistantship during my MS. Funding is easier to get for PhD students, but MS students can get it too.

>>2737140
>You do CFD? You are a god amongst engineers.
Heh, fuck yea. Obviously I'm extremely biased, but yes, CFD is a badass field. Pure math, numerical methods, software engineering, fluid mechanics, intuition... we've got it all.

>>2737124
>>2737124

bumping for simple cylinder advice

I've checked all of my books and asked my teachers to no avail.

>>2737137
>Uhm, any advice for another suspected ADHD twat?
Yeah, get some concerta/adderall.

>>2737100
>how is your love-life?
Well, I live with my gf / pseudo-fiance. Could be worse.
>how is your family?
Pretty great. Some people think it's weird that I'm in my late 20s and still "in school" and living on grad student stipends, but others are summarily impressed that I'm getting a PhD in a demanding field.

>>2737164
Sorry I missed that. You can just add the pressures. Simple gage pressure -- if it's 5atm inside and 1atm outside, it's just a 4atm gage pressure on the inside, done.

If it's *really* thick, you'd have to account for the pressures acting on different surface areas.

>>2737124

We're going to need just a little more info. If the pressures are uniform and the pressure vessel is thin-walled, then yes.
If you're submerging part of the vessel (or creating some other situation where the environment pressures aren't equal), then you may have to take into account vessel deformation. If this is for an early to mid undergraduate course though, then I would doubt this.
All pressure vessels in undergrad are well-behaved though.

Why are you on 4chan? Don't tell me /sci/ is the main reason you come here.

>>2737127
gtfo you're one of those fags who tries to a get trophy wife by telling her you're a "rocket scientist". You're no scientist you're an oompa loompa of science, now get the fuck off my /sci/ faggot.

>>2737109
Do you have any work experience?

>>2737168

i asked the second questions. thanks and good to hear that it's all well :)

>>2737180

Cool, thanks.

>>2736929
>fluid mechanics
have you ever come across or did anything related to turbulence in He4-II (superfluid helium)?
Is it reasonable to go to study it? (reasonable in means of being able to find a job in the future)

>>2737204
>Why are you on 4chan? Don't tell me /sci/ is the main reason you come here.
I'm a light 4chan user. Grad students waste time on the internet too, ya know. Just the occasional /b/rowse for luls, /s/ porn, and some /sci/, though this place is generally disappointing.


Case in point, the prevalence of losers that don't even have a degree that think their B in freshman physics enables them to debate the differences between academic fields they don't understand >>2737205

>>2737213
>Do you have any work experience?
Yes, in a couple small companies. I don't have drive to get into the big aerospace corporations.

>>2737229
>have you ever come across or did anything related to turbulence in He4-II (superfluid helium)?
Is it reasonable to go to study it? (reasonable in means of being able to find a job in the future)
Never anything directly with helium, but I expect it doesn't really matter. Turbulence is a crazy field with tons of research going on.

>"I am an old man now, and when I die and go to heaven there are two matters on which I hope for enlightenment. One is quantum electrodynamics, and the other is the turbulent motion of fluids. And about the former I am rather optimistic."

I don't work in the area, but I assume that superfluid turbulence research is just standard Navier-Stokes coupled with electrodynamics and chemistry modeling.

Why aren't you answering my question about the rocket gun? You misunderstood and thought I was referring to a recoilless rifle. What recoilless rifle is bolt action? Answer please. Thanks.

I want to simulate friction between a lot of `boxes' modeled by a spring between themselves and with several springs connected between them and the ground.

Which numerical algorithm should I use to go from the acceleration (the forces are determined) to movement and position?

Is Runge Kutta 4 always the answer?

>>2737294
The gyrojet and HARP answers covered that as well as possible. It's been done. What more do you want?

>>2737307
Well, a spring isn't going to be right... you're going to need some damping in there, right? It's friction, after all.

RK4 isn't always the answer, but it'd generally a good first try. Stiffness problems will become apparently pretty quickly...

>>2737330

Yeah I'm going to push the first box through a spring of constant velocity and add some viscosity for dampening.

Could you go into the aeroplane business if space proves too unlucrative? Can you really expect to get a job in a field with so little commercial incentive anyway? (space that is)

Can chemists work in rocket science or is it all engineers?

>>2737378
>Could you go into the aeroplane business if space proves too unlucrative?
I'm actually much more on the aeronautical side anyway.
>Can you really expect to get a job in a field with so little commercial incentive anyway? (space that is)
Well, yes. Obviously it's easier to pay the bills with military work, but the space industry isn't all that small either.

>>2737384
>Can chemists work in rocket science or is it all engineers?
Of course! Combustion is obviously very important...

You said homework was allowed so I'll try asking you for help in my fluid mechanics laboratory, the main object of of the laboratory is to find the coefficient of discharge (C):

You have a cylindrical container filled with water that has a orifice at a distance "H" below the level of the water, you also have the diameter of both the container and the small orifice (therefore you have Area 1 and Area 2), you are to determine the velocity at which the fluid leaves the container (WITHOUT assuming that the level of the water on top is = 0 , that is, you can't use torricelli's directly).
The velocity must be determined as a function of h (which is the length "h" in the drawing)

So far for this part I only used Bernoulli's and Fluid Continuity and got
v2 = sqrt(2gh/(1-(A2/A1)^2))
so far I think I did it right.

The next step is to find the discharge as a function of "h" (this is to be plotted later), besides measuring "h" you are also allowed to measure the time that it takes to reach "h" and the volume that leaves the container in that time "t".

For this part I'm kinda stuck, how should I find the discharge in terms of h?
and the last step is to figure what the Discharge coefficient is by using:
Q_e = Experimental discharge
Q_i = ideal discharge
C = Coefficient of discharge

Q_e = C * Q_i

this is after I take several measurements at different "h" 's ( and the times it takes to get there and the volume it discharges in that time if necessary) and apply least squares (which I believe will be of the form y= ax^b)

>>2737460
forgot pic, and hope you have time to help.

Hey OP, you probably don't remember me. I was the recent B.Sc. mechatronics grad, and we had a little conversation about grad school. This isn't a question, but I'd like to say that I appreciate that talk. I've got my acceptance and a research project worked out and I'll be starting my M.Sc. in September working on wind power development (mostly because our new water tunnel wont be finished for May, but they'll be giving me a job to help set up and calibrate the thing so its not all bad).

Cheers. :D

How far along are you in your PhD work? Where do you plan to go once you're done?

Just curious. I'm doing a PhD in MechE and I'm not entirely sure what I'm doing with my life yet... aerospace engineering sounds pretty interesting though.

>>2737460
I'm not exactly sure what you mean by not being able to use the Torricelli result, since obviously you are using it...

you've already got the equation for velocity as a quadratic in terms of h. solve for h. then apply the volumetric flow rate, and integrate with time to get h as a function of time.

>>2737486
awesome, i remember you. i also do work in wind power actually =)

>>2737507
I've got a couple years left. Not really sure between academia and industry right now. Just living the dream!

I'm currently in first year vehicle engineering and I
plan on swapping to physics because I hate
applied sciences like sound & vibrations and the like.
This will probably be very unbeneficial to my
future job prospects.

What's your take on this?

>>2737588
I did the exact opposite.

>>2737588
You think physicists get to ignore reality like sound and vibrations?

Depends if you want to teach high school or not...

>>2736929
>Claims to be a rocket "scienist"
>actually just some shitty "engineer"

Do you know any actual rocket scientists?

>>2737588

What did you have the last time you had lunch?

What's the usual lunch you pack to work, etc.

>>2737617

What kind of potential is there for an aerospace engineer to do propulsion systems research? I want to do some kind of research on scramjets and nuclear propulsion in the future.

>>2736929
>engineering

Have you always been an underachiever?

>>2736952

>>2737642
>>2737637
>>2737630
>>2737620
trying too hard

>>2737635
Tons of potential. I do scramjets now.

>>2737620
>Do you know any actual rocket scientists?
Do you have a college degree?

>>2737648
>>2736929

wat is the biggest dick you ever taken?

>>2737617

No but my current programme seems to focus an
awful lot on things such as that, I'm more intradested
in Q.M. and other hippie modern physics, of which
there is none where I am atm.

>>2737655
>7" Starting
I wish...

Oh it's this thread again.

Fucking self-absorbed

>>2737654
>avoids the question

Maybe one day, if you work hard enough, you can work for a real rocket scientist.

Also, why do you insist on calling yourself a scienist, if you are just a shitty engineering? Are you that fucking Embarrassed?

>>2737635
Bump.

>>2737654
>>2736929
>Calls himself a "scientist" cause he is embarrased he is only an "engineer"

>>2736929
So it is true then!
Even engineers know that engineering is shit.

>>2737671
>19 year old virgin
>saw people on /sci/ saying engineers are fags
>decides he wants to be cool too
>collects large amounts of homosexual pornography
>has no baccalaureate and no work experience
>posts pictures of cocks

I love OP

>>2736929

I think I am a terrible human being. I hear about people like you and I am fraught with envy, because I have neither the skill nor the drive to succeed in engineering and somewhere along the line I became fixated on making money instead of improving the human condition. I walk past established scientists' doors in our science departments and feel ashamed, knowing that with each passing semester I come closer to washing out of my program and ending up a waste of my communities time and money.

Just know OP that you are the subject of incredible envy by at least one person on /sci/, and that when I say "I wish good luck upon you", I say it through the mire of disappointment and misdirected hate that is my life.

I wish good luck upon you.
Whew, that felt good to put down.

>>2737704
It is funny how wrong you are.
Answer the question buddy.

Why are you so ashamed of being an engineering?

>>2736929
>>2737722

Sure is same fag.

>>2736929
>>2737722
>>2737715
Nice samefag OP

>>2737722
>implying you need skill to be an engineer

>>2737747
>>2737740

I don't care what you think. That message was for OP and only OP knows for sure that it's not same faggotry.

>>2737722
You are only a waste if you let it go. I had some major setbacks in my life before I found my niche. Quitting is easier than forging ahead, but when you break through that wall and look back, the feeling of accomplishing something, and those little 8.5x11 sheets of paper with a couple signatures in frames up on the wall... that's something no one can ever take away from you.

Do it.

>>2737756
>>2737755
Gay hook-up thread?

>>2737756

Thanks OP. It always helps to know that personal struggles need not be unique to the person and may in fact be shared by quite a few.

/sci/ is shit, but some of the people on it are good examples of human beings.

>>2737756
>>2736929

>>2737704
>>collects large amounts of homosexual pornography
maybe that stuff was already on his computer to begin with

>>2737756

hahaha, late 20s and posting courage wolf?
goddamn thats just sad man. also, an education is grand but you talk about it like theres nothing else in life, double sad man :(

>>2737848
Courage wolf is courageous; what's age got to do with it? Do you think teenagers invented the internet or something?

And I certainly don't think education is everything. One needs a happy, balanced life. But being that this is supposed to be a science and math board, I don't think a discussion about my sex life would be particularly relevant, do you?

>>2737799
>mfw I see Shirley on /sci/

>>2737913

how do i teach myself matlab and python? what software should i learn to use for applied math/modeling? i have a numerical analysis class in a few months and i have never stepped into the applied field before.

>>2736929

>>2738279
never done any programming at all? there's no shortage of beginner matlab tutorial information. it's easy enough that you should be able to learn it as you go through your course materials. just go grab a book from your library and try out some examples.

FWIW, if you've never done any programming before, matlab is going to be much easier for you to pick up.

>>2738306
>>2738222
>>2737796
>>2737778
>>2737752
>>2737747
>>2737725
>>2737691
>>2737683
>>2737671
>>2737655
>>2737642
>>2737637
>>2737630
>>2737620

Sure is samefag in here.

>>2738329

Are you new here?
You know that eveyone calls engineers gay, right? It isn't personal bro.

>>2738329
Engineering butthurt

>>2738329
>>2736929

>>2736929
My retarded cousin got his Phd in engineering. It is good that there are jobs for people like ya'll.