Concept for regulations to improve overtaking

[Zynerji]

I still think that it could be very simple.

Optimize these for thickness, reprofile the leading edge to be more aero, raise the diffusor exit by 100mm, and stack 3 of these across the diffusor exit. Then add an air compressor (not clutchable) to the crank to drive it at a minimum psi.



This would draw more air from the undertray by entrainment(increasing downforce) but would leave 3 stacked air "blades" instead of the upwash that we currently have.

I would call it "The Relaminator", and see if cars can then follow more closely due to the super clean air on their front wing.

[Just_a_fan]

OK I wont go off topic for too long. What is interesting with the fan is that it won't shoot out stones as much as we think. Mainly because it is only providing a moderate velocity increase to bring the velocity under the car in-line to what it would be in clean air. So not as dramatic as the Brabham fan car.

The loss of downforce is due to loss of structure in the airflow. The front wings create lots of carefully designed flows that direct "dirty" air outwards and "clean" below the car (both in association with the bargeboards and other devices). These structures are disrupted/misdirected when following. Sucking a bit of air at the rear won't help that problem.

[PlatinumZealot]

OK I wont go off topic for too long. What is interesting with the fan is that it won't shoot out stones as much as we think. Mainly because it is only providing a moderate velocity increase to bring the velocity under the car in-line to what it would be in clean air. So not as dramatic as the Brabham fan car.

The loss of downforce is due to loss of structure in the airflow. The front wings create lots of carefully designed flows that direct "dirty" air outwards and "clean" below the car (both in association with the bargeboards and other devices). These structures are disrupted/misdirected when following. Sucking a bit of air at the rear won't help that problem.

Don't let me whip my calculations out. You are forgetting about how boundary layers work. Along with other things...
But I don't want to detract from the topic. I will answer in the appropriate thread.

[jjn9128]

OK I wont go off topic for too long. What is interesting with the fan is that it won't shoot out stones as much as we think. Mainly because it is only providing a moderate velocity increase to bring the velocity under the car in-line to what it would be in clean air. So not as dramatic as the Brabham fan car.

The loss of downforce is due to loss of structure in the airflow. The front wings create lots of carefully designed flows that direct "dirty" air outwards and "clean" below the car (both in association with the bargeboards and other devices). These structures are disrupted/misdirected when following. Sucking a bit of air at the rear won't help that problem.

Don't let me whip my calculations out. You are forgetting about how boundary layers work. Along with other things...
But I don't want to detract from the topic. I will answer in the appropriate thread.

So you're not so much talking about a fan car but about boundary layer blowing/injecting high Pdyn adjacent to surface to reduce Pstat closer to isolation??? Just sucking under the car isn't going to make the floor work better in a wake, the flow is complex and directional... Maybe that's where I've been confused...

Loss of downforce is twofold, 1) is lower Pdyn in wake which directly reduces Pstat on surfaces, 2) is redirection of flow fields down the car, means lower Pdyn from wheels/whatever ends up in undesirable areas.

[PlatinumZealot]

It is a fan car but not entirely.. It is a hybrid In that the floor still relies on the front splitter and the use of sealing vortices and the expansion of the dufuser.... However there are ducts from the fan leading to openings under the floor at startegic areas.

The fan is sucking alone. The low static pressure in front of the tunnels towards the fan reduces the growth of the boundary layers (iti may even relaminarize it) in the targeted areas and also influences vortex migration in others. Generally it increases the velocity of the air under the floor to recover downforce.

[jjn9128]

I still think that it could be very simple.

Optimize these for thickness, reprofile the leading edge to be more aero, raise the diffusor exit by 100mm, and stack 3 of these across the diffusor exit. Then add an air compressor (not clutchable) to the crank to drive it at a minimum psi.

http://www.nueair.com/product/images/SI ... fe_dia.jpg

This would draw more air from the undertray by entrainment(increasing downforce) but would leave 3 stacked air "blades" instead of the upwash that we currently have.

I would call it "The Relaminator", and see if cars can then follow more closely due to the super clean air on their front wing.

hmmmm that is an interesting idea... I was trying to come up with a similar solution using the exhaust at one point. Perhaps not what you're suggesting as a means of 'cleaning' the wake, but to increase the average mass flow at critical points (onto the front wing and floor of a competitor) in the wake. I'm not sure if it would work in the way you suggest though...

From my original post up-wash is not the worst thing in the wake and is even beneficial for increasing the mass flow onset to the following car, so I don't think that getting rid of up-wash is the best solution.

[Shrieker]

I think the question was more aimed at the fact that in a corner, the wake created at any instant will move "forwards" following the tangent of the car's trajectory, and thus move away from the car's trajectory. In a straight, the wake moves forwards while staying in the car's trajectory, and thus will interact with the wake created a bit before and a bit afterwards. This would change the nature of the dusturbance to the air.
I for one find the idea that the wake might be very different in straights than it is in corners quite interesting. Doubly so since, in that case, the situation in corners is extremely difficult to reproduce in wind tunnel (regarding wake).

But today, the teams have access to advanced onboard aero testing apparatus. In fact, they use them quite often. These devices can be used to collect wake data to improve the concept of a car that is insusceptible to dirty air in corners.

[Zynerji]

I still think that it could be very simple.

Optimize these for thickness, reprofile the leading edge to be more aero, raise the diffusor exit by 100mm, and stack 3 of these across the diffusor exit. Then add an air compressor (not clutchable) to the crank to drive it at a minimum psi.

http://www.nueair.com/product/images/SI ... fe_dia.jpg

This would draw more air from the undertray by entrainment(increasing downforce) but would leave 3 stacked air "blades" instead of the upwash that we currently have.

I would call it "The Relaminator", and see if cars can then follow more closely due to the super clean air on their front wing.

hmmmm that is an interesting idea... I was trying to come up with a similar solution using the exhaust at one point. Perhaps not what you're suggesting as a means of 'cleaning' the wake, but to increase the average mass flow at critical points (onto the front wing and floor of a competitor) in the wake. I'm not sure if it would work in the way you suggest though...

From my original post up-wash is not the worst thing in the wake and is even beneficial for increasing the mass flow onset to the following car, so I don't think that getting rid of up-wash is the best solution.

My idea was to simply entrain the air coming from the floor to leave a clean stream for the following cars front wing.

If upwash has benefit, the top of the 3 air knives can be angled upwards to still generate the effect.

[Just_a_fan]

Don't let me whip my calculations out. You are forgetting about how boundary layers work. Along with other things...
But I don't want to detract from the topic. I will answer in the appropriate thread.

Go on then, get your calculations out!

[godlameroso]

It is a fan car but not entirely.. It is a hybrid In that the floor still relies on the front splitter and the use of sealing vortices and the expansion of the dufuser.... However there are ducts from the fan leading to openings under the floor at startegic areas.

The fan is sucking alone. The low static pressure in front of the tunnels towards the fan reduces the growth of the boundary layers (iti may even relaminarize it) in the targeted areas and also influences vortex migration in others. Generally it increases the velocity of the air under the floor to recover downforce.

https://www.youtube.com/watch?v=-v67vVTGgIs

Old tech, not surprised if not already in use in F1. They take very little power to run, and can clean up turbulent air flows.

[PlatinumZealot]

Don't let me whip my calculations out. You are forgetting about how boundary layers work. Along with other things...
But I don't want to detract from the topic. I will answer in the appropriate thread.

Go on then, get your calculations out!

Too early, too early. Those equations are not pretty either. But in layman's terms for a given momentum as the pressure differential across the surface ( dp/dx) increases the boundary layer thickness is less. So simply put, having the fan reduces energy loss under the floor - that energy saved, you can use it for less drag or more downforce up to you.

[holeindalip]

https://www.youtube.com/watch?v=GZWiysL ... ture=share


Already shows an f1 car at the end of the video

[jjn9128]

Don't let me whip my calculations out. You are forgetting about how boundary layers work. Along with other things...
But I don't want to detract from the topic. I will answer in the appropriate thread.

Go on then, get your calculations out!

Too early, too early. Those equations are not pretty either. But in layman's terms for a given momentum as the pressure differential across the surface ( dp/dx) increases the boundary layer thickness is less. So simply put, having the fan reduces energy loss under the floor - that energy saved, you can use it for less drag or more downforce up to you.

I would also be interested in seeing a proof or at least a schematic of how it works/feeds into the undertray.

The drag of an F1 car is dominated by induced drag, not just from downforce but sideforce too. In fact viscous drag is a tiny part of overall drag - I can't see active aerodynamics as a means of reducing drag within the current spec like you suggest. Same as the controversy over the matte paint on the Red Bull being a means of reducing skin friction a few years back. Where I could see active aero being used to remove the necessity for creating induced drag to improve downforce (i.e. no more turning vanes, bargeboards, vortex generators). I don't know if such systems fit within my concept for better nose-to-tail racing or not.

[Vyssion]

Go on then, get your calculations out!

Too early, too early. Those equations are not pretty either. But in layman's terms for a given momentum as the pressure differential across the surface ( dp/dx) increases the boundary layer thickness is less. So simply put, having the fan reduces energy loss under the floor - that energy saved, you can use it for less drag or more downforce up to you.

I would also be interested in seeing a proof or at least a schematic of how it works/feeds into the undertray.

The drag of an F1 car is dominated by induced drag, not just from downforce but sideforce too. In fact viscous drag is a tiny part of overall drag - I can't see active aerodynamics as a means of reducing drag within the current spec like you suggest.

^ this...

I'm curious to see what equations youre referring to as well; I have the feeling that you may be implying the opposite of one effect under one type of geometry as being the flow physics for the opposite geometry. If flow over a boundary occurs when there is a pressure decrease in the direction of flow, the fluid will accelerate and the boundary layer will become thinner (e.g. usually occurs in converging geometries), however, with a diverging geometry (e.g. a diffuser), the problem shifts from one that involves pressure inducing a boundary layer acceleration/thinning, to one of momentum. When the pressure increases in the direction of flow the situation is very different. Fluid outside the boundary layer has enough momentum to overcome this pressure which is trying to push it backwards. The fluid within the boundary layer has so little momentum that it will very quickly be brought to rest, and possibly reversed in direction. If this reversal occurs it lifts the boundary layer away from the surface, causing separation. I'm not sure that a fan will have enough of an impact on the momentum of the boundary layer within the diverging tunnels so as to "re-energize it" and make it thinner.

Given that the boundary layer thickness (and by extention) the coefficient of skin friction of a body is related to the Reynolds Number of the system, the fact that Re is a function of velocity means that at the surface, your local Re will be zero and thus you will not be able to totally eliminate the boundary layer. Given such a short distance that the diffusers cover at the moment, Im not sure whether the "increase" in velocity that a fan could impart to the air flow in there when the air is already travelling at ~300km/hr etc, would do enough to make a noticable difference in the thickness of the boundary layer. You also have the issue at the moment where teams employ a concave diffuser in order to rapidly increase the cross sectional area of the diffuser at the expense of generating a permanent separation bubble; there is still a net positive, and so again, I am not sure of how that solution would compare to forcing the boundary layer to remain attached and using some sort of a "sucking" fan instead.

[godlameroso]

Too early, too early. Those equations are not pretty either. But in layman's terms for a given momentum as the pressure differential across the surface ( dp/dx) increases the boundary layer thickness is less. So simply put, having the fan reduces energy loss under the floor - that energy saved, you can use it for less drag or more downforce up to you.

I would also be interested in seeing a proof or at least a schematic of how it works/feeds into the undertray.

The drag of an F1 car is dominated by induced drag, not just from downforce but sideforce too. In fact viscous drag is a tiny part of overall drag - I can't see active aerodynamics as a means of reducing drag within the current spec like you suggest.

^ this...

I'm curious to see what equations youre referring to as well; I have the feeling that you may be implying the opposite of one effect under one type of geometry as being the flow physics for the opposite geometry. If flow over a boundary occurs when there is a pressure decrease in the direction of flow, the fluid will accelerate and the boundary layer will become thinner (e.g. usually occurs in converging geometries), however, with a diverging geometry (e.g. a diffuser), the problem shifts from one that involves pressure inducing a boundary layer acceleration/thinning, to one of momentum. When the pressure increases in the direction of flow the situation is very different. Fluid outside the boundary layer has enough momentum to overcome this pressure which is trying to push it backwards. The fluid within the boundary layer has so little momentum that it will very quickly be brought to rest, and possibly reversed in direction. If this reversal occurs it lifts the boundary layer away from the surface, causing separation. I'm not sure that a fan will have enough of an impact on the momentum of the boundary layer within the diverging tunnels so as to "re-energize it" and make it thinner.

Given that the boundary layer thickness (and by extention) the coefficient of skin friction of a body is related to the Reynolds Number of the system, the fact that Re is a function of velocity means that at the surface, your local Re will be zero and thus you will not be able to totally eliminate the boundary layer. Given such a short distance that the diffusers cover at the moment, Im not sure whether the "increase" in velocity that a fan could impart to the air flow in there when the air is already travelling at ~300km/hr etc, would do enough to make a noticable difference in the thickness of the boundary layer. You also have the issue at the moment where teams employ a concave diffuser in order to rapidly increase the cross sectional area of the diffuser at the expense of generating a permanent separation bubble; there is still a net positive, and so again, I am not sure of how that solution would compare to forcing the boundary layer to remain attached and using some sort of a "sucking" fan instead.

Most F1 cars aren't struggling for downforce at 300kph+, quite opposite in fact, they want to shed downforce/induced drag at that speed, as they have more than enough downforce to navigate turns at those speeds save for at most three turns on any given track. Where F1 cars struggle at, the biggest performance difference in terms of aero comes in the low and mid speed corners. The speed range of 120-260kph is where good aero makes a difference for the vast majority of tracks, and conditions. Given the same engine, improving downforce in this speed range will make a bigger difference than downforce above it.

Aside from Copse in Silverstone, turn 11 in Hungary, Pouhon in Spa, turns 3 & 9 in Barcelona, Turn 11 & 12 in Australia, Turn 7 in China, turn 1 in Japan, and turns 5, 6 & 12 in Sepang there are no real corners in the 260kph+ speed range.