How diffuser accelerate air in front of it?

[IQ 240]

1)Diffuser reduce speed and increase pressure,so how diffuser accelerate air in front of it if we have adverse pressure gradient situation? Wouldnt be better that we put lower pressure(instead high) on end which will "pull"/accelarate air in front of it?
Air allways naturally goes from high to low pressure region,but here we has adverse pressure gradient,because low pressure is under floor but high pressure is at diffuser..

2)What is pressure distribution at F1 floor/diffuser?

[Dr. Acula]

You have to differentiate what high and low pressure means in this case. The pressure in the diffusor ist still lower than atmospheric in this case.
The working of the floor-diffusor combination can be explained by bernoulli's principle. If you idealize the system, you can look at it as a constant massairflow under the entire underbody, which naturally means the flow must be faster where the cross-section is smaller otherwise the flow wouldn't be constant and faster flow means lower static pressure, at least as long as you stay subsonic.

[Dipesh1995]

1)Diffuser reduce speed and increase pressure,so how diffuser accelerate air in front of it if we have adverse pressure gradient situation? Wouldnt be better that we put lower pressure(instead high) on end which will "pull"/accelarate air in front of it?
Air allways naturally goes from high to low pressure region,but here we has adverse pressure gradient,because low pressure is under floor but high pressure is at diffuser..

2)What is pressure distribution at F1 floor/diffuser?

https://i.stack.imgur.com/bbUnF.jpg

viewtopic.php?f=6&t=15007

Ogami musashi's explanation in the above thread, in particular, covers the fundamentals well.

[IQ 240]

You have to differentiate what high and low pressure means in this case. The pressure in the diffusor ist still lower than atmospheric in this case.
The working of the floor-diffusor combination can be explained by bernoulli's principle. If you idealize the system, you can look at it as a constant massairflow under the entire underbody, which naturally means the flow must be faster where the cross-section is smaller otherwise the flow wouldn't be constant and faster flow means lower static pressure, at least as long as you stay subsonic.

Wouldn be better to put wing low pressure side on the end of floor,so low pressure from wing will "suck/accelarate air under floor,so in this case we dont have adverse pressure gradient-situation?

[Dr. Acula]

Wouldn be better to put wing low pressure side on the end of floor,so low pressure from wing will "suck/accelarate air under floor,so in this case we dont have adverse pressure gradient-situation?

Any other questions?

[Smokes]

basically the mass flow rate going into the diffusor should equal the mass flow rate exiting the difussor

mass flow rate = rho x Q

Where rho is the fluid density

And Q is the volumetric flow.

Q= rho x flow velocity x Area

by changng the area you change the flow velocity, the bigger flow velocity change the bigger the pressure drop.

see here for the rest of the math

https://www.engineersedge.com/fluid_flo ... _14001.htm