Ferrari SF21

[gordonthegun]

I'm always amazed at how big the cooling outlets need to be:

https://cdn-1.motorsport.com/images/mgl ... sf21-1.jpg

This always makes me ask this question:

If the teams put a 150mm thick panel of 10mm Nomex honeycomb inside that outlet, would the relamination of the airstream be helpful to the rear wing? Would it cause much drag if the total frontal area of the leading edge of the panel was 30mm/Sq? That stuff is super thin and light. I'd love to see if it could clean up the wake of the car.

You'd still get some vortex shedding from the bluff rear end of the panel causing a von Karman vortex street, so there'd still be vorticity coming from the back of the opening. So the panel would need to streamlined but even then you'd still get alternating vortices being shed. And these would be long vortices across the width of the cooling outlet.

In reality, I doubt the flow coming from the outlets affects the rear wing that much anyway. That is being fed by freestream (nearly) air. The upwash from the wing affects the flow after it has left the cooling outlets and it will be mixed in with the flow coming from the diffuser.

I do wonder whether the flow of hot air from the cooling outlets actually helps the diffuser by effectively reducing the pressure difference above/below it. After all, the whole point of the coke bottle is to direct fast air over the top of the diffuser. Fast air being "low pressure" air. The hot air coming from the cooling outlets will be similarly "low pressure" being hot and moving too. (Using "low pressure" in the basic sense)

I'm not an expert, so forgive if I'm wrong, but low pressure over the top of the diffuser means lift and not downforce. The low pressure must be under the diffuser and the more the pressure over the diffuser is high, the more downforce you get.
Right?

[Just_a_fan]

I'm not an expert, so forgive if I'm wrong, but low pressure over the top of the diffuser means lift and not downforce. The low pressure must be under the diffuser and the more the pressure over the diffuser is high, the more downforce you get.
Right?

No. The diffuser's job is to slow the air down (yes, that seems counterintuitive) to meet the airflow around the car. The slower the air is above the diffuser's rear lip, the bigger the speed difference and the more the flow gets messy and draggy and less effective. That's why the teams spend so much time and effort getting clean airflow to the rear of the floor behind the sidepods. Note that the air they're sending that way is fast and over the top of the diffuser. If the air above the diffuser's rear lip was slow, it would be relatively high pressure (compared to the flow in the diffuser). That slow flow would then want to flow in to the low pressure zone and cause the diffuser to choke.

The low pressure that results in downforce isn't actually in the diffuser - it's at the throat point where the flat floor meets the diffuser. After that point, the diffuser is working to extract the air from the throat and slow it down to meet the freestream. F1 cars use a big kink to over-expand the air just after the throat and then use the various strakes in the diffuser to control the flow and prevent it from just becoming a big separated mess. The strakes channel the flow but also create vortices that help to stop it separating and choking the diffuser. It's the low pressure at the kink that pulls air from below the floor. The diffuser's job is to clear that air out of the way once it's been through the kink.

I seem to remember that Ferrari were the first to use this big kink. Before they did it, everyone's floor smoothly lifted in to the diffuser.

[One and Only]

I'm always amazed at how big the cooling outlets need to be:

https://cdn-1.motorsport.com/images/mgl ... sf21-1.jpg

This always makes me ask this question:

If the teams put a 150mm thick panel of 10mm Nomex honeycomb inside that outlet, would the relamination of the airstream be helpful to the rear wing? Would it cause much drag if the total frontal area of the leading edge of the panel was 30mm/Sq? That stuff is super thin and light. I'd love to see if it could clean up the wake of the car.

You'd still get some vortex shedding from the bluff rear end of the panel causing a von Karman vortex street, so there'd still be vorticity coming from the back of the opening. So the panel would need to streamlined but even then you'd still get alternating vortices being shed. And these would be long vortices across the width of the cooling outlet.

In reality, I doubt the flow coming from the outlets affects the rear wing that much anyway. That is being fed by freestream (nearly) air. The upwash from the wing affects the flow after it has left the cooling outlets and it will be mixed in with the flow coming from the diffuser.

I do wonder whether the flow of hot air from the cooling outlets actually helps the diffuser by effectively reducing the pressure difference above/below it. After all, the whole point of the coke bottle is to direct fast air over the top of the diffuser. Fast air being "low pressure" air. The hot air coming from the cooling outlets will be similarly "low pressure" being hot and moving too. (Using "low pressure" in the basic sense)

How fast is the air coming out of the cooling outlets? I presume if it is much slower than surrounding airflow it would only create disturbances.

[gordonthegun]

I'm not an expert, so forgive if I'm wrong, but low pressure over the top of the diffuser means lift and not downforce. The low pressure must be under the diffuser and the more the pressure over the diffuser is high, the more downforce you get.
Right?

No. The diffuser's job is to slow the air down (yes, that seems counterintuitive) to meet the airflow around the car. The slower the air is above the diffuser's rear lip, the bigger the speed difference and the more the flow gets messy and draggy and less effective. That's why the teams spend so much time and effort getting clean airflow to the rear of the floor behind the sidepods. Note that the air they're sending that way is fast and over the top of the diffuser. If the air above the diffuser's rear lip was slow, it would be relatively high pressure (compared to the flow in the diffuser). That slow flow would then want to flow in to the low pressure zone and cause the diffuser to choke.

The low pressure that results in downforce isn't actually in the diffuser - it's at the throat point where the flat floor meets the diffuser. After that point, the diffuser is working to extract the air from the throat and slow it down to meet the freestream. F1 cars use a big kink to over-expand the air just after the throat and then use the various strakes in the diffuser to control the flow and prevent it from just becoming a big separated mess. The strakes channel the flow but also create vortices that help to stop it separating and choking the diffuser. It's the low pressure at the kink that pulls air from below the floor. The diffuser's job is to clear that air out of the way once it's been through the kink.

I seem to remember that Ferrari were the first to use this big kink. Before they did it, everyone's floor smoothly lifted in to the diffuser.

OK, thanks, I'll think about it tonight before I fall asleep, the moment I understand the most.

[RaceFan1]

I'm not an expert, so forgive if I'm wrong, but low pressure over the top of the diffuser means lift and not downforce. The low pressure must be under the diffuser and the more the pressure over the diffuser is high, the more downforce you get.
Right?

No. The diffuser's job is to slow the air down (yes, that seems counterintuitive) to meet the airflow around the car. The slower the air is above the diffuser's rear lip, the bigger the speed difference and the more the flow gets messy and draggy and less effective. That's why the teams spend so much time and effort getting clean airflow to the rear of the floor behind the sidepods. Note that the air they're sending that way is fast and over the top of the diffuser. If the air above the diffuser's rear lip was slow, it would be relatively high pressure (compared to the flow in the diffuser). That slow flow would then want to flow in to the low pressure zone and cause the diffuser to choke.

The low pressure that results in downforce isn't actually in the diffuser - it's at the throat point where the flat floor meets the diffuser. After that point, the diffuser is working to extract the air from the throat and slow it down to meet the freestream. F1 cars use a big kink to over-expand the air just after the throat and then use the various strakes in the diffuser to control the flow and prevent it from just becoming a big separated mess. The strakes channel the flow but also create vortices that help to stop it separating and choking the diffuser. It's the low pressure at the kink that pulls air from below the floor. The diffuser's job is to clear that air out of the way once it's been through the kink.

I seem to remember that Ferrari were the first to use this big kink. Before they did it, everyone's floor smoothly lifted in to the diffuser.

You will want to accelerate the air through the diffuser to generate downforce. That's been part of wing design discussions forever.

https://en.wikipedia.org/wiki/File:Equa ... ng1_en.svg

[Just_a_fan]

I'm not an expert, so forgive if I'm wrong, but low pressure over the top of the diffuser means lift and not downforce. The low pressure must be under the diffuser and the more the pressure over the diffuser is high, the more downforce you get.
Right?

No. The diffuser's job is to slow the air down (yes, that seems counterintuitive) to meet the airflow around the car. The slower the air is above the diffuser's rear lip, the bigger the speed difference and the more the flow gets messy and draggy and less effective. That's why the teams spend so much time and effort getting clean airflow to the rear of the floor behind the sidepods. Note that the air they're sending that way is fast and over the top of the diffuser. If the air above the diffuser's rear lip was slow, it would be relatively high pressure (compared to the flow in the diffuser). That slow flow would then want to flow in to the low pressure zone and cause the diffuser to choke.

The low pressure that results in downforce isn't actually in the diffuser - it's at the throat point where the flat floor meets the diffuser. After that point, the diffuser is working to extract the air from the throat and slow it down to meet the freestream. F1 cars use a big kink to over-expand the air just after the throat and then use the various strakes in the diffuser to control the flow and prevent it from just becoming a big separated mess. The strakes channel the flow but also create vortices that help to stop it separating and choking the diffuser. It's the low pressure at the kink that pulls air from below the floor. The diffuser's job is to clear that air out of the way once it's been through the kink.

I seem to remember that Ferrari were the first to use this big kink. Before they did it, everyone's floor smoothly lifted in to the diffuser.

You will want to accelerate the air through the diffuser to generate downforce. That's been part of wing design discussions forever.

https://en.wikipedia.org/wiki/File:Equa ... ng1_en.svg

The acceleration occurs at the throat. The diffuser doesn't accelerate, it evacuates the throat. The diffuser helps evacuation by slowing the air coming out of the throat in a controlled way. If the slowing happens incorrectly, you get choking of the flow

[gordonthegun]

This time again the test of the new floor (for Silverstone? Shouldn't a better floor be used always?)

[Sevach]

Really weird to understand what Ferrari is doing with regards to upgrades, this floor was used friday but removed for the race.
Now they'll test it again.

Anyway the nose from underneath, with nostrils into cape.

[Stu]

Really weird to understand what Ferrari is doing with regards to upgrades, this floor was used friday but removed for the race.
Now they'll test it again.

Anyway the nose from underneath, with nostrils into cape.
https://cdn-1.motorsport.com/images/mgl ... tail-1.jpg

They are really pushing the cape concept with that. Very complex flows, very 3-d (almost a bi-plane!)

[Zynerji]

Really weird to understand what Ferrari is doing with regards to upgrades, this floor was used friday but removed for the race.
Now they'll test it again.

Anyway the nose from underneath, with nostrils into cape.
https://cdn-1.motorsport.com/images/mgl ... tail-1.jpg

They are really pushing the cape concept with that. Very complex flows, very 3-d (almost a bi-plane!)

Looks like a full-on front diffusor... Brilliant!

[gordonthegun]

Ferrari finally to race with new Z-floor with 6 small elements in front of the rear tyres and 3 fins a little further on (dark photo but that's it):

[Sevach]

Photos from saturday suggest both cars will be equipped with this floor.

[LM10]

Ferrari finally to race with new Z-floor with 6 small elements in front of the rear tyres and 3 fins a little further on (dark photo but that's it):

https://cdn-1.motorsport.com/images/mgl ... sf21-1.jpg

They seem to have combined elements of two prior floors. If you go back to page 31 and look at my post you’ll see that the 6 small elements in front of the rear tyre were on the floor with the 3 fins a little further, but there was no fin making the floor a Z shape one. The fin making the Z shape was on the floor with only 3 elements in front of the rear tyre. So they went and combined 6 elements + 3 fins + Z shape. If I’m not mistaken.

Since Portimao there have not been any new parts on the car. Only existing ones being put on and off the car in various combinations.

[gordonthegun]

Ferrari finally to race with new Z-floor with 6 small elements in front of the rear tyres and 3 fins a little further on (dark photo but that's it):

https://cdn-1.motorsport.com/images/mgl ... sf21-1.jpg

They seem to have combined elements of two prior floors. If you go back to page 31 and look at my post you’ll see that the 6 small elements in front of the rear tyre were on the floor with the 3 fins a little further, but there was no fin making the floor a Z shape one. The fin making the Z shape was on the floor with only 3 elements in front of the rear tyre. So they went and combined 6 elements + 3 fins + Z shape. If I’m not mistaken.

Since Portimao there have not been any new parts on the car. Only existing ones being put on and off the car in various combinations.

Since Portimao, the only new part has been the front wing, introduced in France. Now the floor, will there be a next one?

[F1NAC]

Since development is already stopped we can maybe expect some upgrades but probabl on micro level. So no major changes on the shapes of current aerosurfaces.