godlameroso wrote: ↑
Tue Feb 01, 2022 11:07 pm
Just_a_fan wrote: ↑
Tue Feb 01, 2022 7:23 pm
Why would the air move from a region of low pressure to a region of high pressure?
It doesn't, it always goes from high to low. You create higher than atmospheric pressure by moving through the air. The air fills the space you leave as you displace the air via turbulence, as that is the quickest way to return to atmospheric equilibrium.
https://www.simscale.com/api/v1/project ... ssible.png
A vortex needs energy to sustain itself, the tendency of air will be to come to rest and become "static" pressure if no energy is added to it. If you add energy to the air by displacing it, in the proper way, you get a vortex. The low and high pressure components are separated and in equilibrium because of the energy being fed into the system.
The vortices are generated by differential pressure across a device e.g. the Y250 is generated by the discontinuity formed where the central mandated neutral section of the front wing meets the inner end of the active part of the front wing. Here, the air is being accelerated by the wing and air is drawn laterally in to this air across the lower surface of the neutral section. So we have lateral movement that starts the vortex.
The end of the neutral section is visible here, for example:
Once the air leaves the rear edge of this device, that's it. It starts to deteriorate by what is effectively a boundary layer drag between the spinning core and the "still" air around it. No additional energy is being added until the vortex meets a similar vortex being generated by a different device elsewhere on the car e.g. the bargeboard. By creating a number of similar vortices, the devices on the bargeboard have an additive effect on the main vortex. This helps to keep the Y250 vortex going and with sufficient spin to help direct air around the car.
Keep in mind that these vortices are short lived beasties. They traverse the entire length of the car in a fraction of a second, and once they leave the last vortex generating surface behind, they start to deteriorate, and soon burst and disperse in to ever smaller eddies. At racing speeds, the air leaving the trailing edge of the front wing is behind the rear of the car in 0.1s or less.
I assume your water jet video is trying to show that you can spin up the vortices that way too. You can use a lateral jet but it would need to be in a container such as a vortex dust extractor. If you just blow air at an unrestrained vortex, it'll just move laterally and, of course, lose some of its coherence.
Turbo says "Dumpster sounds so much more classy. It's the diamond of the cesspools." oh, and "The Dutch fans are drunk. Maybe"