|
|
02-10-2012, 10:29 PM
|
#15
|
Senior Member
Tiffin Owners Club Freightliner Owners Club
Join Date: Feb 2008
Location: Pensacola, Florida
Posts: 5,173
|
Regardless of what my wife thinks, no.
__________________
Travel well, travel safe,
Jim
2006 Tiffin Phaeton - 2011 Cadillac SRX
|
|
|
|
Join the #1 RV Forum Today - It's Totally Free!
iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!
You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!
|
02-11-2012, 09:14 AM
|
#16
|
Senior Member
Monaco Owners Club
Join Date: Mar 2008
Location: Houston, Texas
Posts: 434
|
Quote:
Originally Posted by djbmsu
The fact is wind chill ONLY effects skin, nothing else
period !
|
(advanced apology to all engineers...)(and anyone else who reads all of this)
Any wind increases the temperature loss of an object to the ambient temperature on all objects exposed to the wind, not just skin. This is why you can blow on hot coffee to reduce the surface temperature.
Wind cannot reduce the temperature below the ambient temperature, only to the actual temperature. If the temperature is 32 degrees Fahrenheit or below, the time it takes for an object to freeze will be shortened.
Conversely, if you place an ice cube in a non-freezing room, the ice cube will melt faster if you blow room air on it.
It is true that wind affects the perception of temperature on our skin, which explains the term WINDCHILL, which is the perceived measurement of heat transfer theory on a human face at 5 feet above ground level, blah, blah, blah.
The original post asks the effect on water. The answer is "Yes," it speeds heat loss on all exposed objects; and "No," it will not freeze unless the air temperature is already freezing.
Respectfully submitted,
(I had surgery on my knee and have ENTIRELY TOO MUCH TIME to kill)
__________________
Bud
US Army Major, Retired
'08 Monaco Diplomat SFT,
'11 Z-71 4X4 toad
|
|
|
02-11-2012, 12:22 PM
|
#17
|
Senior Member
iRV2 No Limits Club
Join Date: May 2011
Location: Tempe, AZ
Posts: 1,833
|
Quote:
Originally Posted by Tsronco
Does water freeze if windchill is below 32 degrees but the actual temp is above 32 degrees?
|
Only if the water has been connected to a flux capacitor.
|
|
|
02-11-2012, 12:35 PM
|
#18
|
Senior Member
Gulf Streamers Club
Join Date: Mar 2011
Posts: 181
|
Did u know that -40F is also -40 celsius, thats the only point I believe they come together.
found that out snowmobiling in canada once upon a time . A little , no a lot off topic but??? and thats without the Flux Capacitor
__________________
Bob, Julie and Izzy (Usually on all 4)
2008 Gulfstream Gladiator, Super C Toyhauler
2007 Chevy Suburban LTZ / Readybrake.
2010 Harley Ultra Classic
|
|
|
02-11-2012, 03:25 PM
|
#19
|
Senior Member
Monaco Owners Club
Join Date: Mar 2011
Location: Almond, Wisconsin
Posts: 1,512
|
Wind chill is the opposite of heat index. It makes cold really cold and heat index makes hot realy hot, I think, maybe, sort of.
__________________
2006 Monaco Camelot 40 PAQ 400ISL - Toad Jeep Grand Cherokee - DW is the Nagivator. Retired to travel and everything revolves around the price of diesel.
|
|
|
02-11-2012, 04:38 PM
|
#20
|
Senior Member
Join Date: Sep 2011
Posts: 982
|
Wind chill is the opposite of heat index only in the context of human perception of the actual temperature. They are determined very differently.
Wind chill is a simple formula based solely on wind speed and temperature - as already stated above.
NWS Wind Chill Index
Heat index is another simple formula based solely on humidity and temperature.
National Weather Service Heat Safety
And yes, -40C = -40F and is the only point where that happens.
|
|
|
02-11-2012, 06:04 PM
|
#21
|
Senior Member
Join Date: Feb 2002
Location: Aguanga, CA, USA
Posts: 239
|
Sorry but I believe the consensus answer here is incorrect. Assuming you're talking about an exposed water surface and not water in a sealed container, there would be evaporative cooling and the water would be a little cooler than the air temperature (evaporation would be increased by moving air over the surface). So it would be possible to have some freezing even though the air temperature remained just above the freezing point.
|
|
|
02-11-2012, 06:51 PM
|
#22
|
Senior Member
Join Date: Sep 2011
Posts: 982
|
So js, can the ∆H_evaporation of (average city water at 1ATM) ever by greater than ∆H_fusion(0C) + ∆H_liquid(ambient -> 0C) of (average city water)? In the context of the OP the answer is exceedingly doubtful. Hence, the consensus answer IS CORRECT. And please, let's not even delve into the Mpemba effect.
Context is everything in a forum question, especially a scientific one. It's not reasonable to list every extenuating/control condition when providing a simple working answer to a simple question with simple conditions and stay within the simple context asked. Then - for reasons already posted - the posts pile on taking things out of that context and hammering every conceivable - often laboratory conditions required - alternative.
The presumed context of the OP's post on an RV forum is that of a puddle, bucket, or hose-full of water (as in a connection from the pedestal to the RV). Most of these contexts do not even expose the water directly to the air. Hence evaporative cooling is not even a factor.
In the case of a bucket or puddle, the surface area of the exposed water, if aligned so as to maximize wind induced evaporative effects, will STILL require the ∆H_evaporation to be greater than the combined effects of 1) thermal transmission from the warmer water immediately below the wind exposed water (wind also keeping the water continually mixed) and 2) exceeding the ∆H_fusion(0C) + ∆H_liquid(ambient -> 0C) of the water in order for ice to form.
In practical working terms in the context of this scenario, the water will NOT freeze.
|
|
|
02-11-2012, 07:10 PM
|
#23
|
Member
Join Date: Aug 2010
Posts: 37
|
If its 25 degrees outside and the humidity is 80% what is the heat index?
|
|
|
02-11-2012, 07:19 PM
|
#24
|
Senior Member
Join Date: Sep 2011
Posts: 982
|
CO_kid
Heat index is considered valid only if the actual temperature is above 27 °C (80 °F), dew point temperatures greater than 12 °C (54 °F), and relative humidities higher than 40% .
http://www.campbellsci.com/documents...s/heatindx.pdf
|
|
|
02-11-2012, 07:27 PM
|
#25
|
Senior Member
Monaco Owners Club
Join Date: Mar 2008
Location: Houston, Texas
Posts: 434
|
__________________
Bud
US Army Major, Retired
'08 Monaco Diplomat SFT,
'11 Z-71 4X4 toad
|
|
|
02-11-2012, 08:49 PM
|
#26
|
Senior Member
Join Date: Sep 2011
Posts: 982
|
|
|
|
02-12-2012, 10:26 AM
|
#27
|
Member
Join Date: Aug 2010
Posts: 37
|
Quote:
Originally Posted by ottffss
|
I know I was just being funny.
|
|
|
02-12-2012, 10:34 AM
|
#28
|
Senior Member
Newmar Owners Club
Join Date: Jan 2010
Posts: 4,589
|
It's amazing how many different ways NO can be expressed.
__________________
2007 Newmar DSDP 4023
Discovery is seeing what everyone else has seen and thinking what no one else has thought.
If you want to see what man made go East; if you want to see what God made go West.
|
|
|
|
|
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
|
|
Posting Rules
|
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
HTML code is Off
|
|
|
|
» Recent Discussions |
|
|
|
|
|
|
|
|
|
|
|
|
|