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1

The idea is all based on scaling laws, which is a very common theme in turbulence. As I mentioned in a comment, this assumes that the energy produced is equal to the energy dissipated. The energy produced is proportional to $u^2$. The turbulence is assumed to dissipate according to some time scale. A reasonable time scale is the eddy-turnover time, or ...


2

Yes, the increased air density in winter will increase drag and thus fuel consumption, especially on the highway. The density is increased by even more than the 10% you propose, since the air is usually drier in the winter than in the summer, and dry air is denser than wet air (because the molar mass of N2 is much greater than that of H20). Also, the ...


2

I think you are right about the 10% increase air density in the winter and this thorough answer on the Bicycle Stack Exchange supports your observation about the effect when cycling. Drag forces are directly proportional to air density so that would have an effect on fuel consumption. There is another factor this is also significant - in regions where ...


0

You said "at constant pressure." I think you mean without wind, correct? (Because you also mentioned wind.) Just so there won't be confusion let's remove wind from the equation and assume the air is completely motionless at colder temperatures. Air molecules condense or shrink in cooler temperatures - causing higher pressure. So yes, cooler ...



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