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The retraction boundary layer chokes the underside of the high DF rear wing. The spoon one avoids this because there's more space for the retraction boundary layer.

What is a retraction boundary layer? Can you explain this is more layman terms

n_anirudh wrote: ↑

08 May 2021, 18:46

What is a retraction boundary layer? Can you explain this is more layman terms

The retraction is the angled part of the endplate that points towards the center of the car.

Notice the high downforce rear wing is closer to that part of the end plate.

The air that flows over the end plate retraction creates a boundary layer that was interfering with the airflow of the main element on the rear wing. The spoon shaped wing has a larger distance between the end plate retraction and main plane. Thus the boundary layers of each surface interact less.

godlameroso wrote: ↑

08 May 2021, 20:43

n_anirudh wrote: ↑

08 May 2021, 18:46

What is a retraction boundary layer? Can you explain this is more layman terms

The retraction is the angled part of the endplate that points towards the center of the car.

Notice the high downforce rear wing is closer to that part of the end plate.

The air that flows over the end plate retraction creates a boundary layer that was interfering with the airflow of the main element on the rear wing. The spoon shaped wing has a larger distance between the end plate retraction and main plane. Thus the boundary layers of each surface interact less.

https://files.catbox.moe/a2u1rf.jpg

Does that mean that they won't really be able to run the high downforce rear wing and get the full benefit unless they make some changes to it?

SiLo wrote: ↑

09 May 2021, 01:23

godlameroso wrote: ↑

08 May 2021, 20:43

n_anirudh wrote: ↑

08 May 2021, 18:46

What is a retraction boundary layer? Can you explain this is more layman terms

The retraction is the angled part of the endplate that points towards the center of the car.

Notice the high downforce rear wing is closer to that part of the end plate.

The air that flows over the end plate retraction creates a boundary layer that was interfering with the airflow of the main element on the rear wing. The spoon shaped wing has a larger distance between the end plate retraction and main plane. Thus the boundary layers of each surface interact less.

https://files.catbox.moe/a2u1rf.jpg

Does that mean that they won't really be able to run the high downforce rear wing and get the full benefit unless they make some changes to it?

It means when they get the high downforce wing working, it'll be a nice upgrade.

The staggered underplates these days have very little to do with that, the endplates already cause far more slowing and disruption to the flow as it is, the real reason is the effective aspect ratio is much closer to ideal in the centre of the wing than by the endplates, you start getting a lot of spanwise flow near the plates unless it's controlled.

The outer mounts make little difference, most teams have them canted vertically slightly to actually direct airflow there, there's actually less 'blockage' than there was with the old vertical mounts.

godlameroso wrote: ↑

08 May 2021, 20:43

n_anirudh wrote: ↑

08 May 2021, 18:46

What is a retraction boundary layer? Can you explain this is more layman terms

The retraction is the angled part of the endplate that points towards the center of the car.

Notice the high downforce rear wing is closer to that part of the end plate.

The air that flows over the end plate retraction creates a boundary layer that was interfering with the airflow of the main element on the rear wing. The spoon shaped wing has a larger distance between the end plate retraction and main plane. Thus the boundary layers of each surface interact less.

https://files.catbox.moe/a2u1rf.jpg

I think you should start again at the basic theory of boundary layers if you forgot or did not read it before. I am not going to assume you haven't!

Not an aerodynamicist, but boundary layers start as a wedged shaped, zero thinkness then expands as the fluid moves further down the surface and into laminar then turbument regimes.

In other words... The boundary layers of the wing underside and the inward bent part that you call the retraction don't interact. They are too small to interact at that point. The flows are even laminar too if you look at the flow-vis, meaning fairly thin boundary layers. I understand what you intend to say, but boundary layer is not the word you want to use. So i have to say your hylothesis is not valid.

See the wegde cross section of a boundary layer below:



I know what you wanna say though.. But its not boundary layer....

You mean the interaction of the wakes perhaps?

Why using terms you havent hresearched! It is dangerous and what is called misinformation or fake news as the Trumpians would say.

I will guide you my friend, we go on an adventure together. What you say about wings is true, if and only if, the leading edge is relatively flat to oncoming air. F1 wings are NOT relatively flat to oncoming air, they expose the underside of the leading edge making it a high pressure surface with a thick boundary layer. This is because curving the leading edge of the underside upwards increases the strength of the trailing edge suction side. All F1 wings are scoops, the leading edge has a lip that curves upward. This is to channel more airflow to the low pressure side as that is the MOST important side of the wing.

PhillipM wrote: ↑

09 May 2021, 01:35

The staggered underplates these days have very little to do with that, the endplates already cause far more slowing and disruption to the flow as it is, the real reason is the effective aspect ratio is much closer to ideal in the centre of the wing than by the endplates, you start getting a lot of spanwise flow near the plates unless it's controlled.

The outer mounts make little difference, most teams have them canted vertically slightly to actually direct airflow there, there's actually less 'blockage' than there was with the old vertical mounts.

Mercedes makes them canted downwards to increase the expansion of air at the end plates. And it's also more inline with the counter rotating vortecies shed by the floor. Those counter rotating vortecies are traveling downward at the endplates when looking at the car from behind

If the new mounts were ever an issue, every team would have adopted the same design by now, the fact they didn't, and that teams used to run spoon wings for years with straight endplates, still suggests the canted endplate mounts have little to do with it.

PhillipM wrote: ↑

09 May 2021, 02:42

If the new mounts were ever an issue, every team would have adopted the same design by now, the fact they didn't, and that teams used to run spoon wings for years with straight endplates, still suggests the canted endplate mounts have little to do with it.

What are you talking about?

godlameroso wrote: ↑

08 May 2021, 20:43

n_anirudh wrote: ↑

08 May 2021, 18:46

What is a retraction boundary layer? Can you explain this is more layman terms

The retraction is the angled part of the endplate that points towards the center of the car.

Notice the high downforce rear wing is closer to that part of the end plate.

The air that flows over the end plate retraction creates a boundary layer that was interfering with the airflow of the main element on the rear wing. The spoon shaped wing has a larger distance between the end plate retraction and main plane. Thus the boundary layers of each surface interact less.

https://files.catbox.moe/a2u1rf.jpg

Based on flat plate theory, those BL are no more than a few cm thick ( may be lesser) and by your logic I still fail to see how the spoon wing is further from the endplate. The central part is closer . There would be a redistribution of pressure overall in that region, but I don't see how BL would interact given the distance.

If there is a higher pressure, the flow would separate and I don't see how the BL would get thicker. Rest of your posts are gibberish TBH or simply that there is a language issue here.

godlameroso wrote: ↑

09 May 2021, 02:23

I will guide you my friend, we go on an adventure together. What you say about wings is true, if and only if, the leading edge is relatively flat to oncoming air. F1 wings are NOT relatively flat to oncoming air, they expose the underside of the leading edge making it a high pressure surface with a thick boundary layer. This is because curving the leading edge of the underside upwards increases the strength of the trailing edge suction side. All F1 wings are scoops, the leading edge has a lip that curves upward. This is to channel more airflow to the low pressure side as that is the MOST important side of the wing.

That makes it even worse for you. The race car wing boundary layers are only a few milimeter thick at worse (assuming no stall).
They wont interfere as you say.

Look at the little flip ups.. Look at the gaps between the front wings. Imagine if the boundary layers were large things? Madness!

So best thing to do is go back to the fundamental theory and check again. Or do a simulation.

CFD sims i used to do the boundary layer is such a fine thing i coudlnt even set it up in my software. Dont ask me about ansys because i remember nothing. But its not this big giant thing that you imagine.
See how close the F1 floor gets to the road. And look at the space in the little gills at the rear of the diffuser. You can just think about it and use ur senses to see that these devices wont work if they had thick boundary layers stuffed up bentween them. Easy reasoning. Nothing to calculate.

PlatinumZealot wrote: ↑

10 May 2021, 05:08

godlameroso wrote: ↑

09 May 2021, 02:23

I will guide you my friend, we go on an adventure together. What you say about wings is true, if and only if, the leading edge is relatively flat to oncoming air. F1 wings are NOT relatively flat to oncoming air, they expose the underside of the leading edge making it a high pressure surface with a thick boundary layer. This is because curving the leading edge of the underside upwards increases the strength of the trailing edge suction side. All F1 wings are scoops, the leading edge has a lip that curves upward. This is to channel more airflow to the low pressure side as that is the MOST important side of the wing.

That makes it even worse for you. The race car wing boundary layers are only a few milimeter thick at worse (assuming no stall).
They wont interfere as you say.

Look at the little flip ups.. Look at the gaps between the front wings. Imagine if the boundary layers were large things? Madness!

So best thing to do is go back to the fundamental theory and check again. Or do a simulation.

CFD sims i used to do the boundary layer is such a fine thing i coudlnt even set it up in my software. Dont ask me about ansys because i remember nothing. But its not this big giant thing that you imagine.
See how close the F1 floor gets to the road. And look at the space in the little gills at the rear of the diffuser. You can just think about it and use ur senses to see that these devices wont work if they had thick boundary layers stuffed up bentween them. Easy reasoning. Nothing to calculate.

Fluttering changes the boundary layer, a surface boundary layer changes significantly depending on how that surface interacts with air. In any case, looks like RBR were able to improve their rear wing by increasing the gap between the end plate retraction and the main plane. Will be interesting to see where else they race their new wing.



This wing gave good top speed while also giving good downforce in the slow corners, that may have been track dependent however.