Tube for thought

[posplayr]

My 1100E has an intake velocity of ~ 22m/s @ 9000rpm (assuming steady flow, 100% volumetric efficiency and 34mm carb bores). Because the total velocity vector will be the square root of the sum of the squares you will need an unobtainable amount of swirl to significantly lower the pressure beyond what it achieves without the swirl. To achieve a 1% increase in the total velocity over the 22m/s you need a tangential velocity (the swirl velocity) of 3.12m/s. In a 34mm bore that equates to a swirl of 5500RPM. And only the very outer portion of the bore achieves that much velocity increase, the rest drops off with the radius it is swirling at from the bore centerline.

Mark

OK I refreshed my memory (it was blearaly correct).

An ideal (potential flow) vortex has a velocity profiles of 1/R (R is distance from the center) so even in practice it gets pretty high velocity (lowering the pressure) right at the center. V can't go to infinity because viscosity starts to come into play.

Vortexes are a fundamental part of fluid dynamics and is what is used to explain circulation which is what generates Lift.

Those aircraft wing tip vortices have a lot of energy in them just generated by the spanwise flow, rounding the tips of the wings.

 

[Blue Falcon]

IIRC, Golf ball dimples are used to convert laminar (smooth flow) to turbulent (chaotic flow) by "tripping the boundary layer". In boundary layer theory, turbulent flow has more energy and can stay attached to the ball longer as it flows around to the back of the ball. This reduces pressure drag. Pressure drag is not really present in a venturi.

On the other hand many guys that do head porting leave ports purposefully rough to improve flow mixing (i.e. turbulence). To a limit it is beneficial.

As pointed out already, trying to spin the flow with vaning or tubes or grooves will also create a certain amount of turbulence along with the axial vortex.

The bottom line is that if you try and create a vortex, you probably increase turbulence and flow at the same time. (some combination of better gas mileage and better power).

The one I bought years ago did not seem to do anything for my 440 4B, but others have reported benefits that could certainly be attributed to the vortex action.

Sharkskin intake

dimpled valves

its a thing already

 

[Blue Falcon]

OK I refreshed my memory (it was blearaly correct).

An ideal (potential flow) vortex has a velocity profiles of 1/R (R is distance from the center) so even in practice it gets pretty high velocity (lowering the pressure) right at the center. V can't go to infinity because viscosity starts to come into play.

Vortexes are a fundamental part of fluid dynamics and is what is used to explain circulation which is what generates Lift.

Those aircraft wing tip vortices have a lot of energy in them just generated by the spanwise flow, rounding the tips of the wings.

we are flying air through a cylinder not an airplane lol... on that note... why not add a honeycomb to the stack? with dimples

 

[posplayr]

Sharkskin intake

dimpled valves

its a thing already

Have at it.

 

[Blue Falcon]

Have at it.

couldn't you see my 450 with a full on racing level intake..... bahahahaha... I would feel like one of those guys that puts $10k rims on a $1k car or a $20k stereo system in a $500 car. Now if I was into the high performance racing bike thing...I would fully look into this... F1 racing seems to be at the leading edge of all this.

 

[posplayr]

couldn't you see my 450 with a full on racing level intake..... bahahahaha... I would feel like one of those guys that puts $10k rims on a $1k car or a $20k stereo system in a $500 car. Now if I was into the high performance racing bike thing...I would fully look into this... F1 racing seems to be at the leading edge of all this.

You would be better off putting golf ball dimples on your helmet. Be the first one on your block.

 

[Blue Falcon]

You would be better off putting golf ball dimples on your helmet. Be the first one on your block.

too late... I'm in Orlando... I have seen every helmet known to man, the cycler's have dimpled helmets. Best one I have seen is a full on custom Boba Fett helmet... fully approved... sweetest helmet I've seen. guy said it was around $1600. It is DOT and SNELL approved. That guy paid more for his helmet than I will have in my bike from purchase to two years of ownership.

edit: the Boba Fett helmet added no significant performance enhancement to the bike/rider.... disclaimer . hehehehehe

dimple motorcycle helmet

 

[sharpy]

wow. this is more reaction then i ever thought. And no one has mentioned its basically a TRUMPet. Even better. So presuming i was a rich person with a well sorted 1000S superbike. It be ok to go get some plastic 3D stacks made and see if any effect. Trouble is im not rich. dont have a 1000s Superbike but i will have a tougher streeter than my current 1000 one day but even then i wont be running filter less carbs. Ohh and those grooves are semi circle. just cant tell in that pic. I was too lazy to make larger grooves as it would involve breaking into the other surface and have to make some extensions to suit. Thanks heaps everyone
Opps. This is where everyone can call me a wa*ker... just for looks in the pits on a race stand, would the grooved stacks on the RHS be in opposite direction to the 2 stacks on the LHS. Mite make more "bench racing" chat or get me punched on the nose for being a smart-ass.

 

[posplayr]

we are flying air through a cylinder not an airplane lol... on that note... why not add a honeycomb to the stack? with dimples

You are clearly struggling with a priori synthetic analysis.

 

[Cipher]

I bet it got him loads of women though.

 

[Guest]

OK I refreshed my memory (it was blearaly correct).

An ideal (potential flow) vortex has a velocity profiles of 1/R (R is distance from the center) so even in practice it gets pretty high velocity (lowering the pressure) right at the center. V can't go to infinity because viscosity starts to come into play.

Vortexes are a fundamental part of fluid dynamics and is what is used to explain circulation which is what generates Lift.

Those aircraft wing tip vortices have a lot of energy in them just generated by the spanwise flow, rounding the tips of the wings.

I see what you are talking about, you are thinking a vorex like you can get when dumping water out of a bottle and you put a spin to it. I was thinking more just spiral flow. I don't think you could generate the forces required in the intake to get air to behave in the same manner. The forces generating wingtip vortices are much higher than what OP is working with. BTW, the 1% velocity increase I calculated comes from ~8 degrees of angle on the spiral flow. While I don't think the ridges in OP will ever do much to redirect the flow, 8 degrees is probably possible with some vanes across the stack opening. I don't know if it would achieve anything of note, but it might be possible.

F1 racing seems to be at the leading edge of all this.

That's because they have the money to hire the smartest people and buy the best equipment and it matters to them because they are chasing such ridiculously small margins.

wow. this is more reaction then i ever thought. And no one has mentioned its basically a TRUMPet. Even better. So presuming i was a rich person with a well sorted 1000S superbike. It be ok to go get some plastic 3D stacks made and see if any effect. Trouble is im not rich.

A trumpet has a much different function than a velocity stack, though. As for the 3D printing, my local library has a printer that can be used for a pretty nominal fee. Check around your area and see if there is any sort of maker's group, technical school or similar that offers a cheap 3D printing option. I bet even Shapeways wouldn't be prohibitively expensive for a set: https://www.shapeways.com/

I bet it got him loads of women though.

And we all know that is the true measure of an idea!:lol:


Mark

 

[posplayr]

I see what you are talking about, you are thinking a vorex like you can get when dumping water out of a bottle and you put a spin to it. I was thinking more just spiral flow. I don't think you could generate the forces required in the intake to get air to behave in the same manner. The forces generating wingtip vortices are much higher than what OP is working with. BTW, the 1% velocity increase I calculated comes from ~8 degrees of angle on the spiral flow. While I don't think the ridges in OP will ever do much to redirect the flow, 8 degrees is probably possible with some vanes across the stack opening. I don't know if it would achieve anything of note, but it might be possible.


Mark

You can look up the measure of Circulation in a vortex,but is probably some alfa*CONSTANT where constant relates to the integral of the 1/R function is 2 or 3 dimensions. Alfa relates to total intensity of circulation.

Regardless of alfa, 1/R==> infinity as R==>0 meaning velocity increases to the limit of the viscous shear forces at the center of the vortex regardless of alfa. Your formula just doesn't apply. If you want to calculate the peak velocity calculate the maximum velocity supported by the viscous shear forces.

The principle clearly works, the only question is only how well it is implemented. We know for example that a vortices are created in a number of ways in nature; water going down a drain, wind devils in the desert, tornados, hurricanes.

All of these are due to Coriolis forces acting on a fluid. Recall Coriolis forces are forces on a body due to linear velocity in a rotating frame. In the rotating frame of the Earth, that means that any rising or lowering (with respect to the center of the earth)will cause a Coriolis force (and without checking) is apparently oriented along the (vertical) velocity vector.

If water going down a drain, can form a vortex where the pressure distribution is represented by the depression in the surface, I'm not sure it would be that hard to generate a vortex of some magnitude which will in theory have the limit of velocity always at it's center.

 

[Blue Falcon]

You can look up the measure of Circulation in a vortex,but is probably some alfa*CONSTANT where constant relates to the integral of the 1/R function is 2 or 3 dimensions. Alfa relates to total intensity of circulation.

Regardless of alfa, 1/R==> infinity as R==>0 meaning velocity increases to the limit of the viscous shear forces at the center of the vortex regardless of alfa. Your formula just doesn't apply. If you want to calculate the peak velocity calculate the maximum velocity supported by the viscous shear forces.

The principle clearly works, the only question is only how well it is implemented. We know for example that a vortices are created in a number of ways in nature; water going down a drain, wind devils in the desert, tornados, hurricanes.

All of these are due to Coriolis forces acting on a fluid. Recall Coriolis forces are forces on a body due to linear velocity in a rotating frame. In the rotating frame of the Earth, that means that any rising or lowering (with respect to the center of the earth)will cause a Coriolis force (and without checking) is apparently oriented along the (vertical) velocity vector.

If water going down a drain, can form a vortex where the pressure distribution is represented by the depression in the surface, I'm not sure it would be that hard to generate a vortex of some magnitude which will in theory have the limit of velocity always at it's center.

too much to multi-quote.....with all us smarty-pants have said... the real questions... in non-Mensa speak

Cost/Gain

1. Would there be any significant increase in performance just by adding the horn.
A. You would have to modify so much of the entire intake to truly see any measurable increase that the cost would drastically outweigh the gain - daily riders

2. Cool factor?
A. Yes, would have a cool factor - marketing/fancy color/cool name/pod combo

3. Who could use it?
A. Hard core racers - would need a team to make mods and fine tune everything.

4. If you were to make it would it sell?
A. Go back to 2... people will buy anything with the right marketing. Just don't make any outrageous claims. Here is a tag line you could use and be OK.

"Using the same technology that Formula 1 engineers use in their engines"

With all we have said.... great idea, try it out, don't expect any measurable results....and make it look cool.

 

[posplayr]

too much to multi-quote.....with all us smarty-pants have said... the real questions... in non-Mensa speak

Cost/Gain

1. Would there be any significant increase in performance just by adding the horn.
A. You would have to modify so much of the entire intake to truly see any measurable increase that the cost would drastically outweigh the gain - daily riders

2. Cool factor?
A. Yes, would have a cool factor - marketing/fancy color/cool name/pod combo

3. Who could use it?
A. Hard core racers - would need a team to make mods and fine tune everything.

4. If you were to make it would it sell?
A. Go back to 2... people will buy anything with the right marketing. Just don't make any outrageous claims. Here is a tag line you could use and be OK.

"Using the same technology that Formula 1 engineers use in their engines"

With all we have said.... great idea, try it out, don't expect any measurable results....and make it look cool.

Yes the biggest factors would be how "pretty" it would be.

 

[sharpy]

And then theres always that claim. "As seen on TV" or even better "Modeled on US engineers thoughts connected to the Space programme and made in Australia" Space claim is that one person does live in Florida. LOL

 

[GregT]

You do realise that if the coriolis force was to be of any use, you'd have to make them with the twist going one way for the Northern hemisphere - and the opposite way for us down here....

Personally, I suspect that it's simply going to give a deeper, more turbulent boundary layer. This might be of use if the intake of the carb was too big for the application.

 

[posplayr]

You do realise that if the coriolis force was to be of any use, you'd have to make them with the twist going one way for the Northern hemisphere - and the opposite way for us down here....

Personally, I suspect that it's simply going to give a deeper, more turbulent boundary layer. This might be of use if the intake of the carb was too big for the application.

EDIT:

In physics, the Coriolis force is an inertial force (also called a fictitious force)[SUP][1][/SUP] that acts on objects that are in motion relative to a rotating reference frame. In a reference frame with clockwise rotation, the force acts to the left of the motion of the object. In one with anticlockwise rotation, the force acts to the right. Though recognized previously by others, the mathematical expression for the Coriolis force appeared in an 1835 paper by French scientist Gaspard-Gustave de Coriolis, in connection with the theory of water wheels. Early in the 20th century, the term Coriolis force began to be used in connection with meteorology. Deflection of an object due to the Coriolis force is called the 'Coriolis effect'.

https://en.wikipedia.org/wiki/Coriolis_force



Not sure you really understand what a Coriolis force is. It is ANY linear motion in a rotating frame, not just the earth's rotating frame. I brought up naturally occurring vortices to demonstrate that significant forces can get generated with very low angular rate vectors(i.e. earth rate).

Look at equation 3.10 on page 31

the +w X m V term is the cross product of an angular momentum vector with a velocity vector.




http://www.dtic.mil/dtic/tr/fulltext/u2/283911.pdf


Sorry for the dated reference; first one to come up.

 

[Blue Falcon]

EDIT:


https://en.wikipedia.org/wiki/Coriolis_force



Not sure you really understand what a Coriolis force is. It is ANY linear motion in a rotating frame, not just the earth's rotating frame. I brought up naturally occurring vortices to demonstrate that significant forces can get generated with very low angular rate vectors(i.e. earth rate).

Look at equation 3.10 on page 31

the +w X m V term is the cross product of an angular momentum vector with a velocity vector.

View attachment 49946


http://www.dtic.mil/dtic/tr/fulltext/u2/283911.pdf


Sorry for the dated reference; first one to come up.

oh for pete's sake.....ram air the dam carbs...build and intake that takes air from the front of the bike... let's put pin wheels on it to tell us when we are up to speed and have a control valve that opens at speed...lets also put in an electrostatic filter that zaps any contaminants and ionizes the air, magnetic fuel rail, and a midget on a tricycle with a tool set... lets add so many metering/control devices we add 30lbs to the bike and offset any gain we would have received.....

Make the horn shiny and with a cool name....ooooo shiny.

 

[posplayr]

oh for pete's sake.....ram air the dam carbs...build and intake that takes air from the front of the bike... let's put pin wheels on it to tell us when we are up to speed and have a control valve that opens at speed...lets also put in an electrostatic filter that zaps any contaminants and ionizes the air, magnetic fuel rail, and a midget on a tricycle with a tool set... lets add so many metering/control devices we add 30lbs to the bike and offset any gain we would have received.....

Make the horn shiny and with a cool name....ooooo shiny.

I figured you would have a overt inclination toward complexity, while everything in discussion is the most fundamental results of physics(i.e. symplicity).

I already told you the best answer, it was your dimpled helmet. Did you mention anything related to wind resistance anywhere in you childish diatribe?

 

[Blue Falcon]

I figured you would have a overt inclination toward complexity, while everything in discussion is the most fundamental results of physics(i.e. symplicity).

I already told you the best answer, it was your dimpled helmet. Did you mention anything related to wind resistance anywhere in you childish diatribe?

no diatribe...but after years of working in the engineering field.. I have learned a few things

1. Law of Parsimony
2. Name brand college grad engineers love SS2CPWNBT "simple solutions to complex problems will not be tolerated"... refer to rule 1
3. Closed minded people never get anything accomplished
4. Black box theory of troubleshooting
5. Engineers never can appreciate sarcasm at any level

There is a reason one of the best helmet manufacturers out there doesn't make the dimpled helmet anymore lol.

Brainstorming is great... but too many hands in the cookie jar.... just never know who didn't wash their hands.

We just all over complicated it...we reinvented the wheel on this one. New and Improved is just the same as the old...little shinier and with a cool name. lol