off the wall idea

[jcs003]

This article has some very good information in it.  Its not directly about carburetors, but it does talk some about laminar/turbulent flow and effect on orifice plates.  Basically our jets are an orifice plate.

http://www-personal.engin.umd.umich.edu/~ratts/me379fil/handouts/viscous/Meriam_Laminar_Flow_Element.pdf

well if you read that article you would realize you are talking nonsense.

john

[Burns363R]

how so?

[jcs003]

how so?

you think you get laminar flow across the jets and you are wrong.  you get transitional flow at best.  you need the air moving very fast to keep feeding the system.  LAMINAR FLOW MOVES SLOWLY!!!!

john

[Burns363R]

Everything i have stated is fact.  I dont see how you are saying its not.  The smoother, less turbulent, or more laminar the flow, the better job the jets are going to do measuring the amount of fuel to mix in.  If you have "more" turbulent flow over the jets, the jets wont meter in the proper amount of fuel proportional to the actual amount of air injested.

Granted this is on a very small scale, and probably doesnt make any difference if the inside of a carburetor was roughed up.  This i dont know.  But the facts still apply.

[Burns363R]

you think you get laminar flow across the jets and you are wrong.  you get transitional flow at best.  you need the air moving very fast to keep feeding the system.  LAMINAR FLOW MOVES SLOWLY!!!!

john

Yes laminar flow moves slowly.  And i see what your saying.  Your point is correct.  What i meant was less turbulent flow the better.  Your correct that no flow would be laminar in a carburator or any of the intake for that matter.  I was only using laminar as a point of reference as less turbulent.   I shouldnt have said that.  I should have said less turbulent.

[fearlessfred]

did you guys kow that most of the air flows on the outer edges of the air horn.harry klemm told me that you could place a silver dollar very close to the carb opening without effecting flow

[Jerry Hall]

Do some calculation for your reynolds number for the air velocity at the smallest area of flow through the carb.  The smallest cross-section is usually at the fuel entry point into the air stream.  Typical  peak velocity in most carburetors easily exceeds 300 feet per second and some engines approach the sonic threshold which is over 1000 feet per second.   I do not have time now to find and do the calculations for the reynolds number.  My intuition tells me the flow will be well into the turbulent region.  

The flow through a round cross-section is always highest in the center of the round cross-section and zero at the theoretical surface.  The flow velocity goes from zero at the surface to a much higher number at the edge of the boundary layer and continues to increases as the distance from the boundary layer increases.

[rsss396]

here is something related to your question, interesting results

[Burns363R]

That appears to be an injected motor.  Those diviets definitely reduce air resistance which would increase flow.  Very cool

[rk88r]

It's even referred to as "golfballed". It doesn't appear that any of the runs had only that mod though.

[rsss396]

The way I read the dyno sheet is the run 046 and 127 are the same setup but 127 has the golf ball effect on the 50mm Wasp stacks and 046 has untouched 50mm wasp stacks

[Jerry Hall]

81 dyno runs were made between run 46 and run 127.  A lot of different changes were probably made during those runs.

There is not enough information in the dyno notes to draw any meaningful conclusion as to what caused what.

[Jerry Hall]

................................Those diviets definitely reduce air resistance which would increase flow.  Very cool

It has been many years since I have studied the effects that the threads on a baseball or dimples on a golf ball have on their trajectory of flight.....I think you may be making some miss-informed conclusions as to why a dimpled golf ball will usually fly further than a non dimpled ball and trying to relate how dimples would affect flow in a confined area like a port.  It is my understanding that the dimples reduce the influence spin has on the ball.  A non dimpled ball that has some forward spin or no spin will not fly as far as a non dimpled ball that has backward spin.  Dimples will add distance and reduce the left right flight deviation to the AVERAGE drive because all drives have some degree of spin.


In a port, increasing the boundary layer thickness reduces the effective flow cross-section. Increasing the boundary layer thickness surrounding a dimpled golf ball does not have any walls or boundaries that will affect what is happening close to the golf ball.  Fluid Mechanics and Gas Dynamics are complex subjects and cannot be mastered reading a few hundred pages on the subjects on the internet.  High-level math and physics are prerequisites for Fluid Mechanics and Gas Dynamics.

[Burns363R]

I have never studied the effects of the dimples.  We studied this somewhat in college many years ago. My only "real world" experience was on Mythbusters.... I know not a great source.   But they where able to reduce the air drag on the car by covering the car in clay and putting patterned dimples over the car.  Even with the additional hundreds of pounds of clay, they increase the MPG by several miles.  

Im not going to dive into the fluid dynamics on this.  I dont have the time, or the memory.  And i will add I could be very wrong.  But it was my understanding that by creating turbulence at each dimple moved the boundary layer further from the car.  . I dont have any proof/math behind this, just kinda imagining it in my head.  So please dont take this as gospel.

here is a statement i found while playing around on the internet. Take it for what it is.  A statement.  

If you want to get deeper into the aerodynamics, there are two types of flow around an object: laminar and turbulent. Laminar flow has less drag, but it is also prone to a phenomenon called "separation." Once separation of a laminar boundary layer occurs, drag rises dramatically because of eddies that form in the gap. Turbulent flow has more drag initially but also better adhesion, and therefore is less prone to separation. Therefore, if the shape of an object is such that separation occurs easily, it is better to turbulate the boundary layer (at the slight cost of increased drag) in order to increase adhesion and reduce eddies (which means a significant reduction in drag). Dimples on golf balls turbulate the boundary layer.

[Burns363R]

Also i read that there where other mods on those dyno pulls.  I knew that looked like to much gain to be true.  Would be interesting to see what if any gain there would be with just the intakes designed like that.  You would think someone would already be doing it.