AbouBenAdhem@lemmy.world 1 day ago
One thing that might be a factor is the Bernoulli effect (moving air has lower pressure than still air). When your head is in moving air but your chest is in relatively still air, that would create a pressure differential that makes it harder to draw air into your lungs. On a motorcycle, your whole body is in moving air so the pressure differential wouldn’t exist.
XeroxCool@lemmy.world 1 day ago
That’s a misunderstanding of the bernoulli effect. It does not say moving fluid has lower pressure as some universal law. It applies to when fluid is moving through the same exact route, as in, inside a pipe or around an object. It does not have anything to do with pressure inside the car vs outside., as it’s a massive, chaotic ball of turbulence where you get both inbound and outbound airflow at the same window or can do tricks to make one window inbound (rear windows) and one window outbound (front). If it were that simple, it’d still be hard to breathe on a motorcycle because your torso is somewhat shielded by the aerodynamics of the headlight/gauge area on a naked. Sport bikes often shield your torso as well, throwing air all at your head, which would cause the same “pressure differential” as the car example. But it doesn’t, because that’s not how it works.
The classic example of this misunderstanding is things like pump pressure/flow rate charts. Flow rate goes up, pressure goes down in the chart. Nothing to do with this principle, everything to do with the pump being a fixed-power device putting out a certain amount of work. It’s more of a power vs torque thing than a fluid principle.
And no, air does not move around a wing/airfoil, speed up on the longer side, and reunute its former molecular siblings at the tail of the airfoil. That’s a mythunderstanding, too. Nothing makes them meet up again.