The scenario. At ambient temperature of 0degC to -5degC car sets off, engine warms up and heater is turned max temp and high blower on with recirculate feature (faster heating, no cold make-up air or venting) and front of car and foot well warms up nicely.

Sometimes when turning a corner there is a sensation of the air temperature changing either hotter or colder.

I am curious if this is attributable to differences in air density and the angular acceleration causing thermosiphon effect or tides in the inversion layers?

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    $\begingroup$ It is not clear what you are asking about. "Sensations" are subjective and physiological/psychological - eg optical illusions. (Why does the effect only happen "sometimes"?) Even if other people have the same sensations, it is difficult to try to explain them using physical concepts. They need to be something which can be measured using scientific instruments. $\endgroup$ – sammy gerbil Nov 10 '16 at 19:46
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    $\begingroup$ I have felt the same sensation. It is caused by the air from the vents (which has a different density than the remainder of the mixed air in the cabin) experiencing a horizontal buoyant force as a result of the pseudo-body-force (horizontal gravity) created by the radial acceleration associated with the cornering. $\endgroup$ – Chet Miller Nov 10 '16 at 21:32
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    $\begingroup$ Consider a helium balloon in a moving car. When the car brakes which direction will the balloon move? $\endgroup$ – Jim Garrison Nov 11 '16 at 2:31
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    $\begingroup$ No, I did read your question more than once before commenting. I am being sceptical about something which (you admit) has not been mentioned before. The description in the 1st paragraph suggests forced convection may be dominant, and I don't see how your suggestions in the last paragraph work. Jim Garrison's example does not require movement of whole packets of air, only transmission of pressure. Optical illusions are not hypnosis but alternative conclusions based on the same sensations. But I accept that your sensations are real; my mention of subjectivity is misplaced, I apologise. $\endgroup$ – sammy gerbil Nov 11 '16 at 12:55
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    $\begingroup$ @KalleMP You are correct. The temporary acceleration creates a pressure gradient front to back and the balloon's buoyancy pushes it towards the lower pressure end (the back). $\endgroup$ – Jim Garrison Nov 11 '16 at 16:58

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