Heat flow by convection can be visualized by Schlieren photography in which density differences can be clearly seen. Schlieren photography is closely related to what we commonly refer to as watching the heat rise off hot asphalt, but is much more sensitive (a paper by Gary Settles gives several examples). Horatio Algeranon (a very punny anonymouse) picked up on this, and found a picture showing that the heat flow from a charcoal grill is pretty much straight up. But even Ethon knew this, if he stands to the side when grilling his liver McClimateAudit burgers, things are relatively cool, but bend over and put his beak above the coals, and sure enough it gets fried.
Which brings up to one of Anthony Watts' favorite surface station views
so how does the heat flow
straight up, heating of the air on the sides in contact with the barrel is minimal as seen by the lack of structure.
We have heard a lot about AC units. We even have the famous Marysville picture
Eli walked by a large one yesterday, there was very little airflow a few feet to the side. Schlieren shows the same
Saturday, August 04, 2007