Them vortex things on the roof?
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29 December 2013, 01:26 AM
#11
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I have to say that tubbytommy has done the best description of these I've ever heard - something about 'Sonic the Hedgehog'.
The theory is that air flowing over the car creates an area of low pressure behind it, and as we all know that produces air flow called 'wind' to rush in to fill the pressure variance.
That wind comes from forward of the car, hence the car faces greater air pressure *, similar to heading into a breeze, which it makes into a gale (if you go fast enough).
I've actually seen this in action.
Travelling up the M6 snow came off my roof, and a very small section actually stayed suspended in the middle of the rear screen, over the boot, for miles, due to the pressure difference/vortex (low pressure area).
However, just like none of us 'ordinary' drivers can utilise - even appreciate - an extra 10bhp neither can we sense the degradation in performance caused by the pressure gradient.
Sonic's gizmo is designed to break up the airflow over the vehicle and prevent this low pressure area, and hence the additional air mass that the car faces.
'Vortex generator' is completely the wrong term. It actually prevents the vortex from forming.
Perrin stiffies are a similar enigma.
They do prevent 'wing flex' and hence enable the car/wing to continually maximise downforce.
However, are any of us able to 'feel' the difference?
* Note - there is also the theory that the vortex, being lower pressure, actually holds the car back, similar to a suction effect.
The theory is that air flowing over the car creates an area of low pressure behind it, and as we all know that produces air flow called 'wind' to rush in to fill the pressure variance.
That wind comes from forward of the car, hence the car faces greater air pressure *, similar to heading into a breeze, which it makes into a gale (if you go fast enough).
I've actually seen this in action.
Travelling up the M6 snow came off my roof, and a very small section actually stayed suspended in the middle of the rear screen, over the boot, for miles, due to the pressure difference/vortex (low pressure area).
However, just like none of us 'ordinary' drivers can utilise - even appreciate - an extra 10bhp neither can we sense the degradation in performance caused by the pressure gradient.
Sonic's gizmo is designed to break up the airflow over the vehicle and prevent this low pressure area, and hence the additional air mass that the car faces.
'Vortex generator' is completely the wrong term. It actually prevents the vortex from forming.
Perrin stiffies are a similar enigma.
They do prevent 'wing flex' and hence enable the car/wing to continually maximise downforce.
However, are any of us able to 'feel' the difference?
* Note - there is also the theory that the vortex, being lower pressure, actually holds the car back, similar to a suction effect.
29 December 2013, 10:19 AM
#14
I have to say that tubbytommy has done the best description of these I've ever heard - something about 'Sonic the Hedgehog'.
The theory is that air flowing over the car creates an area of low pressure behind it, and as we all know that produces air flow called 'wind' to rush in to fill the pressure variance.
That wind comes from forward of the car, hence the car faces greater air pressure *, similar to heading into a breeze, which it makes into a gale (if you go fast enough).
I've actually seen this in action.
Travelling up the M6 snow came off my roof, and a very small section actually stayed suspended in the middle of the rear screen, over the boot, for miles, due to the pressure difference/vortex (low pressure area).
However, just like none of us 'ordinary' drivers can utilise - even appreciate - an extra 10bhp neither can we sense the degradation in performance caused by the pressure gradient.
Sonic's gizmo is designed to break up the airflow over the vehicle and prevent this low pressure area, and hence the additional air mass that the car faces.
'Vortex generator' is completely the wrong term. It actually prevents the vortex from forming.
Perrin stiffies are a similar enigma.
They do prevent 'wing flex' and hence enable the car/wing to continually maximise downforce.
However, are any of us able to 'feel' the difference?
* Note - there is also the theory that the vortex, being lower pressure, actually holds the car back, similar to a suction effect.
The theory is that air flowing over the car creates an area of low pressure behind it, and as we all know that produces air flow called 'wind' to rush in to fill the pressure variance.
That wind comes from forward of the car, hence the car faces greater air pressure *, similar to heading into a breeze, which it makes into a gale (if you go fast enough).
I've actually seen this in action.
Travelling up the M6 snow came off my roof, and a very small section actually stayed suspended in the middle of the rear screen, over the boot, for miles, due to the pressure difference/vortex (low pressure area).
However, just like none of us 'ordinary' drivers can utilise - even appreciate - an extra 10bhp neither can we sense the degradation in performance caused by the pressure gradient.
Sonic's gizmo is designed to break up the airflow over the vehicle and prevent this low pressure area, and hence the additional air mass that the car faces.
'Vortex generator' is completely the wrong term. It actually prevents the vortex from forming.
Perrin stiffies are a similar enigma.
They do prevent 'wing flex' and hence enable the car/wing to continually maximise downforce.
However, are any of us able to 'feel' the difference?
* Note - there is also the theory that the vortex, being lower pressure, actually holds the car back, similar to a suction effect.
And even a kinda compliment to TT at the start
29 December 2013, 10:19 AM
#15
I have to say that tubbytommy has done the best description of these I've ever heard - something about 'Sonic the Hedgehog'.
The theory is that air flowing over the car creates an area of low pressure behind it, and as we all know that produces air flow called 'wind' to rush in to fill the pressure variance.
That wind comes from forward of the car, hence the car faces greater air pressure *, similar to heading into a breeze, which it makes into a gale (if you go fast enough).
I've actually seen this in action.
Travelling up the M6 snow came off my roof, and a very small section actually stayed suspended in the middle of the rear screen, over the boot, for miles, due to the pressure difference/vortex (low pressure area).
However, just like none of us 'ordinary' drivers can utilise - even appreciate - an extra 10bhp neither can we sense the degradation in performance caused by the pressure gradient.
Sonic's gizmo is designed to break up the airflow over the vehicle and prevent this low pressure area, and hence the additional air mass that the car faces.
'Vortex generator' is completely the wrong term. It actually prevents the vortex from forming.
Perrin stiffies are a similar enigma.
They do prevent 'wing flex' and hence enable the car/wing to continually maximise downforce.
However, are any of us able to 'feel' the difference?
* Note - there is also the theory that the vortex, being lower pressure, actually holds the car back, similar to a suction effect.
The theory is that air flowing over the car creates an area of low pressure behind it, and as we all know that produces air flow called 'wind' to rush in to fill the pressure variance.
That wind comes from forward of the car, hence the car faces greater air pressure *, similar to heading into a breeze, which it makes into a gale (if you go fast enough).
I've actually seen this in action.
Travelling up the M6 snow came off my roof, and a very small section actually stayed suspended in the middle of the rear screen, over the boot, for miles, due to the pressure difference/vortex (low pressure area).
However, just like none of us 'ordinary' drivers can utilise - even appreciate - an extra 10bhp neither can we sense the degradation in performance caused by the pressure gradient.
Sonic's gizmo is designed to break up the airflow over the vehicle and prevent this low pressure area, and hence the additional air mass that the car faces.
'Vortex generator' is completely the wrong term. It actually prevents the vortex from forming.
Perrin stiffies are a similar enigma.
They do prevent 'wing flex' and hence enable the car/wing to continually maximise downforce.
However, are any of us able to 'feel' the difference?
* Note - there is also the theory that the vortex, being lower pressure, actually holds the car back, similar to a suction effect.
29 December 2013, 10:52 AM
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I'd be intersted to see if it actually has any positive effect whatsoever.
To me if you are attempting to sort out an Impreza's rear aero you need to channel air onto the rear wing which a properly designed roof spoiler could do much more effectively.
The problem with the Impreza like many saloon cars is the way the rear window is steeply angled from the roof onto a flat boot. Left uchecked a low pressure zone is inevitable (basic fluid dynamics) in the area just behind the rear window meaning that faster flowing air above the roof line actually creates lift and as the rear wing has little to work with to restore any downforce.
A properly designed rear spoiler that channels the air and reduces the low pressure zone would be a far better idea IMO!
Look at the aero on an F1 car to see this explained in much more exaggerated detail as all along the car the bodywork is channelling the airflow right from the front wing to make sure the rear wing and aero optiised bodywork can be used to maximum effect!
To me if you are attempting to sort out an Impreza's rear aero you need to channel air onto the rear wing which a properly designed roof spoiler could do much more effectively.
The problem with the Impreza like many saloon cars is the way the rear window is steeply angled from the roof onto a flat boot. Left uchecked a low pressure zone is inevitable (basic fluid dynamics) in the area just behind the rear window meaning that faster flowing air above the roof line actually creates lift and as the rear wing has little to work with to restore any downforce.
A properly designed rear spoiler that channels the air and reduces the low pressure zone would be a far better idea IMO!
Look at the aero on an F1 car to see this explained in much more exaggerated detail as all along the car the bodywork is channelling the airflow right from the front wing to make sure the rear wing and aero optiised bodywork can be used to maximum effect!
29 December 2013, 12:41 PM
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Cheers guys !
29 December 2013, 02:52 PM
#20
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Lmao I saw this on a subaru and did think it looked soooooo out of place and quite hideous!!! But was curious as to wether it actually done anything??? Lol thank you all for the constructive criticism!
