View Full Version : Fluid Dynamics
Dribble Joy
08-12-03, 18:56
I have a fluid dynamics test in 20 mins.
What are the units used in bernoulli's equation.
I know the answer, I am wondering if anyone knows out there?
For bonus points, what assumptions do we make while using said equation?
Mumblyfish
08-12-03, 19:06
Water is wet. And blue.
Compressible and perfect IIRC.
Units will be standard SI for velocity, pressure and distance.
Unless I've got the wrong one, it's been a while.
/edit - no turbulence probably needs to be assumed too.
D'OH! I dont remember......
Someting about force small divided by area small = force large / area large.....
I think..........
As for assumtions.... The pressure in one area will be equal to the presure in the other area if they are both connected together.
Something or other... I Dont remember..... Need to look at physics notes....
Or am I thinking of something else?
Static pressure.
Dynamic pressure.
Total head.
Gravity head.
considerations:
Flow is steady, density is constant, friction is negligable, and it realtes to two points along ONE streamline (single)...
I cant type out the equation coz i dont remember it, its a pain in the arse long anyway.
Anyway.........
Its probably wrong coz its been AGES since i had any educashin
Peeping Tom
08-12-03, 19:19
nvm you was talking aobut some thing else
K4F
Originally posted by Peeping Tom
edited coz joo changed eet
K4F
omfg
WINNAH!!!!!!!!!!
was I even on the right track?
Me dont remember, must review physics notes....
Hur Hur.... Oath already quoted j00!
And now you're typing with that hand?
Somehow I feel ill reading this.
Originally posted by Dribble Joy
For bonus points, what assumptions do we make while using said equation? bernoulli wasn't getting the mad sex... anything like this was done by someone who wasn't sexed enough... those people end up building crazy shit and advancing the human race... or blowing it up with weapons of mass penis envy...
speaking of sex... k4f lies... it was last week... and he was immediately banned for life from the zoo...
-EDiT_
arr...
The units don't really matter, as long as you are consistent across terms.
The standard equation assumes an incompressible medium, no frictional losses and constant flow.
I learnt my FD stuff in relation to oceanography (and by extension meteorology) so supersonic flows weren't much of an issue, but density changes from salinity gradients were a bitch ;)
[I finished my degree in '89, so there were no fancy schmancy 3D real time CFD packages around then :p)
Dribble Joy
08-12-03, 21:12
Wow, didn't expect anyone to know about it, spangly.
The 'standard' equation, is measured in meters, odd being that it's and energy/head equation in nature. But like kurai said, it's doesn't matter as long as units are consistent.
And yes, assumptions are.
No heat transfer: Q=0
No work done by the system or on the system. W = 0
This means no friction/laminar flow etc. etc.
Incompressible fluid.
(P2 - P1)/eg + (V2 - V1)/2g + z2 - z1 = 0
where e is density, the others are somewhat obvious.
This gives rise to this when Q and W are included:
q + w = (h2 - h2) + 1/2(c2^2 - c1^2) + g(z2 - z1)
The first law of thermo dynamics.
Or summat like that.
P.S. I think I did alright in the test.
Hope you did too DJ! :D
Now if you have any questions on electronics and the like or anything of a computer science nature ie. programming then maybe i could help ya! o_O
Its only been 4 years since i done any pyhsics but hey it was annoing anyways abit like doing noise harmonics in a electronic transmission line system!!!! o_O :eek: 8| O_o
Now thats something that sucked ass!!! :rolleyes:
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