Fluid Dynamics...

Post Reply
User avatar
JacksSmirkingRevenge
Grand Wazoo
Posts: 13516
Joined: Thu Feb 26, 2009 6:56 pm
About me: Half man - half yak.
Location: Perfidious Albion
Contact:
Contact JacksSmirkingRevenge

Fluid Dynamics...

Post by JacksSmirkingRevenge » Sun Jan 02, 2011 5:09 am

Would I be correct in thinking that a gas under pressure cannot expand more quickly than it's own speed of sound regardless of how quickly it is released or what pressure it is at?
Anyone...? :think:
Sent from my Interositor using Twatatalk.
Top
User avatar
mistermack
Posts: 15093
Joined: Sat Apr 10, 2010 10:57 am
About me: Never rong.
Contact:
Contact mistermack

Re: Fluid Dynamics...

Post by mistermack » Mon Jan 03, 2011 1:54 am

Bri wrote:Would I be correct in thinking that a gas under pressure cannot expand more quickly than it's own speed of sound regardless of how quickly it is released or what pressure it is at?
Anyone...? :think:
Sorry, I don't know the answer, but I would imagine it's correct. But what would be relevant is how the pressure of gas affects the speed of sound of that gas.
If you double the pressure, do you double the speed of sound in that gas? Or is the speed of sound related to pressure at all?
The speed of sound in air at 1 bar is about 1000 km per hour ( I think ).
If your gas is compressed at 10 bar, what is the speed of sound in that compressed gas? If it's much higher, then you could have expansion at much more than 1000 kph, until the pressure drops.
While there is a market for shit, there will be assholes to supply it.
Top
User avatar
Feck
.
.
Posts: 28391
Joined: Mon Mar 02, 2009 1:25 pm
Contact:
Contact Feck

Re: Fluid Dynamics...

Post by Feck » Mon Jan 03, 2011 2:00 am

http://www.engineeringtoolbox.com/speed-sound-d_82.html
:hoverdog: :hoverdog: :hoverdog: :hoverdog:
Give me the wine , I don't need the bread
Top
User avatar
charlou
arseist
Posts: 32531
Joined: Thu Jun 28, 2012 2:36 am

Re: Fluid Dynamics...

Post by charlou » Mon Jan 03, 2011 3:15 am

:shock: gas pressure has a speed of sound? :what:

Well I think I'm about to learn something new ... *clicks on link*
no fences
Top
User avatar
Xamonas Chegwé
Bouncer
Bouncer
Posts: 50939
Joined: Thu Feb 26, 2009 3:23 pm
About me: I have prehensile eyebrows.
I speak 9 languages fluently, one of which other people can also speak.
When backed into a corner, I fit perfectly - having a right-angled arse.
Location: Nottingham UK
Contact:
Contact Xamonas Chegwé

Re: Fluid Dynamics...

Post by Xamonas Chegwé » Mon Jan 03, 2011 4:53 am

Sound travels faster in denser substances, so it makes sense that it would travel faster in a compressed gas than in the same gas at 1 atmosphere. I can't quite see why the speed of sound should limit the rate of expansion though. That would depend upon the pressure of the gas it was expanding into - ie. a gas at 5atm would expand much faster into a near vacuum than it would into air at 1atm.

I am not saying that your OP is wrong - just that I have never heard of it before and haven't been able to find anything that backs it up online (in about 5 minutes of exhaustive googling!)
A book is a version of the world. If you do not like it, ignore it; or offer your own version in return.
Salman Rushdie
You talk to God, you're religious. God talks to you, you're psychotic.
House MD
Who needs a meaning anyway, I'd settle anyday for a very fine view.
Sandy Denny
This is the wrong forum for bluffing :nono:
Paco
Yes, yes. But first I need to show you this venomous fish!
Calilasseia
I think we should do whatever Pawiz wants.
Twoflower
Bella squats momentarily then waddles on still peeing, like a horse
Millefleur
Top
epepke
Posts: 128
Joined: Thu Feb 25, 2010 4:30 am
Contact:
Contact epepke

Re: Fluid Dynamics...

Post by epepke » Mon Jan 03, 2011 10:48 am

Yes in the sense of no.

The initial, instantaneous expansion will be no greater than the speed of sound. However, as the gas expands, the speed of sound will drop, but the outer bits of gas will still be going at the same speed, absent resistance from other gas.
Top
User avatar
Tigger
1,000,000,000,000,000,000,000 piccolos
Posts: 15714
Joined: Thu Feb 26, 2009 4:26 pm
About me: It's not "about" me, it's exactly me.
Location: location location.

Re: Fluid Dynamics...

Post by Tigger » Mon Jan 03, 2011 11:06 am

What alarms me is "why", Bri? I know, don't I? :demon:
Image
Seth wrote:Fuck that, I like opening Pandora's box and shoving my tool inside it
Top
User avatar
Feck
.
.
Posts: 28391
Joined: Mon Mar 02, 2009 1:25 pm
Contact:
Contact Feck

Re: Fluid Dynamics...

Post by Feck » Mon Jan 03, 2011 11:11 am

Tigger wrote:What alarms me is "why", Bri? I know, don't I? :demon:
Yes, probably :whisper:
:hoverdog: :hoverdog: :hoverdog: :hoverdog:
Give me the wine , I don't need the bread
Top
User avatar
FBM
Ratz' first Gritizen.
Posts: 45327
Joined: Fri Mar 27, 2009 12:43 pm
About me: Skeptic. "Because it does not contend
It is therefore beyond reproach"
Contact:
Contact FBM

Re: Fluid Dynamics...

Post by FBM » Mon Jan 03, 2011 11:13 am

Feck wrote:
Tigger wrote:What alarms me is "why", Bri? I know, don't I? :demon:
Yes, probably :whisper:
He must've had one tremendous fart to inspire such an in-depth inquiry. I'm impressed.
"A philosopher is a blind man in a dark room looking for a black cat that isn't there. A theologian is the man who finds it." ~ H. L. Mencken

"We ain't a sharp species. We kill each other over arguments about what happens when you die, then fail to see the fucking irony in that."

"It is useless for the sheep to pass resolutions in favor of vegetarianism while the wolf remains of a different opinion."
Top
User avatar
normal
!
!
Posts: 9071
Joined: Thu Mar 26, 2009 4:23 pm
About me: meh
Location: North, and then some
Contact:
Contact normal

Re: Fluid Dynamics...

Post by normal » Mon Jan 03, 2011 11:15 am

Are you making a dangerous gun?
Image
Let us think the unthinkable, let us do the undoable, let us prepare to grapple with the ineffable itself, and see if we may not eff it after all.
                                                                                                                                                                                                                   -Douglas Adams
Top
User avatar
Tigger
1,000,000,000,000,000,000,000 piccolos
Posts: 15714
Joined: Thu Feb 26, 2009 4:26 pm
About me: It's not "about" me, it's exactly me.
Location: location location.

Re: Fluid Dynamics...

Post by Tigger » Mon Jan 03, 2011 11:30 am

Normal wrote:Are you making a dangerous?
:fix:

Isn't "dangerous gun" a tautology?
Image
Seth wrote:Fuck that, I like opening Pandora's box and shoving my tool inside it
Top
User avatar
normal
!
!
Posts: 9071
Joined: Thu Mar 26, 2009 4:23 pm
About me: meh
Location: North, and then some
Contact:
Contact normal

Re: Fluid Dynamics...

Post by normal » Mon Jan 03, 2011 11:31 am

Tigger wrote:
Normal wrote:Are you making a dangerous?
:fix:

Isn't "dangerous gun" a tautology?
More dangerous to the user than factory made guns, I meant :tup:
Image
Let us think the unthinkable, let us do the undoable, let us prepare to grapple with the ineffable itself, and see if we may not eff it after all.
                                                                                                                                                                                                                   -Douglas Adams
Top
User avatar
mistermack
Posts: 15093
Joined: Sat Apr 10, 2010 10:57 am
About me: Never rong.
Contact:
Contact mistermack

Re: Fluid Dynamics...

Post by mistermack » Mon Jan 03, 2011 5:16 pm

Don't guns give a bit of a clue? They shoot bullets at far higher velocities than the speed of sound, so the gasses released must be expanding much faster than the speed of sound in air.
.
While there is a market for shit, there will be assholes to supply it.
Top
User avatar
Tigger
1,000,000,000,000,000,000,000 piccolos
Posts: 15714
Joined: Thu Feb 26, 2009 4:26 pm
About me: It's not "about" me, it's exactly me.
Location: location location.

Re: Fluid Dynamics...

Post by Tigger » Mon Jan 03, 2011 5:21 pm

mistermack wrote:Don't guns give a bit of a clue? They shoot bullets at far higher velocities than the speed of sound, so the gasses released must be expanding much faster than the speed of sound in air.
.
Irrelevant. He's talking about expansion, not explosion.
Image
Seth wrote:Fuck that, I like opening Pandora's box and shoving my tool inside it
Top
User avatar
mistermack
Posts: 15093
Joined: Sat Apr 10, 2010 10:57 am
About me: Never rong.
Contact:
Contact mistermack

Re: Fluid Dynamics...

Post by mistermack » Mon Jan 03, 2011 5:47 pm

Tigger wrote:
mistermack wrote:Don't guns give a bit of a clue? They shoot bullets at far higher velocities than the speed of sound, so the gasses released must be expanding much faster than the speed of sound in air.
.
Irrelevant. He's talking about expansion, not explosion.
Yeh, but the explosion provides the expanding gas that drives the bullet.
.
While there is a market for shit, there will be assholes to supply it.
Top
Post Reply

Return to “Science, Technology & Environment”

Who is online

Users browsing this forum: No registered users and 18 guests