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#141
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RCE wrote:
"Calif Bill" wrote in message hlink.net... "JimH" wrote in message ... actually is the same whether it is tissue or beer cans. sigh Sigh my ass. The reason there is a Wind Chill factor is the wind will carry away the extra BTU's that still air can not. The body's response is that it tries to get to the ambient temperature faster. At the same speed as if the air was xx degrees colder. The Wind Chill factor. Same reason that RCE stated that turbulent flow will transfer more heat. Laminar flow will have a small slow speed component of air right next to the surface. That small bit of air will insulate the surface from the air above. Works with beer cans also. Same reason that a car radiator works with air flowing over it. No fan and hot day and sitting still and you overheat. I agree with everything you posted, including tissue or beer cans, except the effect is not "wind chill". In moving air the tissue and beer can, if warmer or colder than the ambient temperature will cool or warm faster to the ambient temperature than in still air. Wind chill is the apparent lower temperature (than ambient) that living tissue experiences due to it's inability to keep up with the increased heat loss in windy conditions. It is equal to that temperature the tissue would be exposed to if there was no wind. And with that, I am done with this wind chill discussion. It's leaving me cold. Well, I'm glad to see everybody having fun today. :) |
#142
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![]() Short Wave Sportfishing wrote: And with that, I am done with this wind chill discussion. It's leaving me cold. Well, I'm glad to see everybody having fun today. :) it's a sunny 32 degrees here today. gives me hope for tomorrow. and the future forcasts look like the local global cooling might be gradually winding down. But it is still February.... |
#143
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posted to rec.boats
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Reginald P. Smithers III wrote:
Calif Bill wrote: "JimH" wrote in message oups.com... On Feb 9, 12:43 am, "Calif Bill" wrote: "JimH" wrote in message ... "Calif Bill" wrote in message link.net... "JimH" wrote in message ... "Calif Bill" wrote in message hlink.net... "RCE" wrote in message ... "Calif Bill" wrote in message link.net... Wind Chill. I do not think it refers to living tissue. I think the definition is how much heat transfer would occur in still air vs. Moving air. some low speed of air. -15 degrees with a wind chill of -30, says the same heat loss would occur if the temp was -30 and no wind movement. Nothing to do with evaporation but with the tendency of the air to heat up near the warmer object, slowing down heat transfer. The term "Wind Chill" applies *only* to living tissue. It refers to the rate of cooling (limited by the ambient temperature) that occurs to exposed living tissue. The increased rate of cooling can exceed the living tissue's ability to replace the heat lost and things like frostbite can quickly occur. The wind can't make it colder. It only makes the rate of heat transfer and cooling of the object faster. Heat transfer is higher in turbulent flow. Eisboch Did not realize it applied only to human tissue. Thought it was just a rate of heat transfer regards air movement. Glad to see you finally got it. :-) actually is the same whether it is tissue or beer cans. sigh Sigh my ass. The reason there is a Wind Chill factor is the wind will carry away the extra BTU's that still air can not. The body's response is that it tries to get to the ambient temperature faster. At the same speed as if the air was xx degrees colder. The Wind Chill factor. Same reason that RCE stated that turbulent flow will transfer more heat. Laminar flow will have a small slow speed component of air right next to the surface. That small bit of air will insulate the surface from the air above. Works with beer cans also. Same reason that a car radiator works with air flowing over it. No fan and hot day and sitting still and you overheat. Agreed. But the beer or radiator fluid will not go below ambient temperature no matter how much air you blow on it. On the other hand, living tissue will and this is traditionally called the Wind Chill factor. The flesh will not go below ambient temperature. Wind chill is the apparent amount of heat that would be lost if the temperature was lower. If the temperature is 5f and a wind chill is -30f, the flesh will lose heat at the same rate as if there was no wind and the temperature was -30. But the flesh will not go below 5f. If it tried to go below 5f, then the Wind Chill Factor would be the Wind Heating factor. Sigh, you do realize he will never understand it. No, Bill is right. I have attended at least five, possibly six, cold weather rescue/cold water rescue/ hypothermia clinics presented by Dr. Murray Hamlet who used to run the Combat Resources Center at the U.S. Army's Research Institute of Environmental Medicine (or whatever it is called now), Natick, MA. Dr. Hamlet is the world's leading expert on cold and cold weather operations and rescue. Dr. Hamlet says as part of his cold rescue presentations that "the one thing you can count on is that a stiff will be a stiff - the body cannot get any colder than ambient temperature". I'm quoting directly from my notes taken at the 1999 EMS Cold Weather/Water Rescue seminar presented at the USCG Academy, New London,CT. The seminar was for folks involved in paramedic level dive medicine and cold condition SAR - which happened to include me. :) |
#144
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posted to rec.boats
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Tim wrote:
Short Wave Sportfishing wrote: And with that, I am done with this wind chill discussion. It's leaving me cold. Well, I'm glad to see everybody having fun today. :) it's a sunny 32 degrees here today. gives me hope for tomorrow. and the future forcasts look like the local global cooling might be gradually winding down. But it is still February.... It's only 20 here and wind gusting 20/25. I don't know what the "semi-hemi-demi-quasi Real Feel it's still only as cold as the ambient" temperature is, but what ever it is - IT'S FREAKIN' COLD!!! |
#145
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posted to rec.boats
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Short Wave Sportfishing wrote:
Reginald P. Smithers III wrote: Calif Bill wrote: "JimH" wrote in message oups.com... On Feb 9, 12:43 am, "Calif Bill" wrote: "JimH" wrote in message ... "Calif Bill" wrote in message link.net... "JimH" wrote in message ... "Calif Bill" wrote in message hlink.net... "RCE" wrote in message ... "Calif Bill" wrote in message link.net... Wind Chill. I do not think it refers to living tissue. I think the definition is how much heat transfer would occur in still air vs. Moving air. some low speed of air. -15 degrees with a wind chill of -30, says the same heat loss would occur if the temp was -30 and no wind movement. Nothing to do with evaporation but with the tendency of the air to heat up near the warmer object, slowing down heat transfer. The term "Wind Chill" applies *only* to living tissue. It refers to the rate of cooling (limited by the ambient temperature) that occurs to exposed living tissue. The increased rate of cooling can exceed the living tissue's ability to replace the heat lost and things like frostbite can quickly occur. The wind can't make it colder. It only makes the rate of heat transfer and cooling of the object faster. Heat transfer is higher in turbulent flow. Eisboch Did not realize it applied only to human tissue. Thought it was just a rate of heat transfer regards air movement. Glad to see you finally got it. :-) actually is the same whether it is tissue or beer cans. sigh Sigh my ass. The reason there is a Wind Chill factor is the wind will carry away the extra BTU's that still air can not. The body's response is that it tries to get to the ambient temperature faster. At the same speed as if the air was xx degrees colder. The Wind Chill factor. Same reason that RCE stated that turbulent flow will transfer more heat. Laminar flow will have a small slow speed component of air right next to the surface. That small bit of air will insulate the surface from the air above. Works with beer cans also. Same reason that a car radiator works with air flowing over it. No fan and hot day and sitting still and you overheat. Agreed. But the beer or radiator fluid will not go below ambient temperature no matter how much air you blow on it. On the other hand, living tissue will and this is traditionally called the Wind Chill factor. The flesh will not go below ambient temperature. Wind chill is the apparent amount of heat that would be lost if the temperature was lower. If the temperature is 5f and a wind chill is -30f, the flesh will lose heat at the same rate as if there was no wind and the temperature was -30. But the flesh will not go below 5f. If it tried to go below 5f, then the Wind Chill Factor would be the Wind Heating factor. Sigh, you do realize he will never understand it. No, Bill is right. I have attended at least five, possibly six, cold weather rescue/cold water rescue/ hypothermia clinics presented by Dr. Murray Hamlet who used to run the Combat Resources Center at the U.S. Army's Research Institute of Environmental Medicine (or whatever it is called now), Natick, MA. Dr. Hamlet is the world's leading expert on cold and cold weather operations and rescue. Dr. Hamlet says as part of his cold rescue presentations that "the one thing you can count on is that a stiff will be a stiff - the body cannot get any colder than ambient temperature". I'm quoting directly from my notes taken at the 1999 EMS Cold Weather/Water Rescue seminar presented at the USCG Academy, New London,CT. The seminar was for folks involved in paramedic level dive medicine and cold condition SAR - which happened to include me. :) Tom, I realize Bill was correct, I was poking fun at JimH's line when he was saying Bill didn't understand Wind Chill. Bill obviously understood it much better than JimH. |
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