Simple Tunnel ram Question

[MadBill]

It doesn't matter in which direction the air is accelerated, since it is in effect a neutral buoyancy situation. Consider for example a two foot diameter beach ball filled with freshwater. Its volume is 4/3 π r³, so 4.189 cubic feet, weight 62.4 lb./C.F. x 4.189 = 261.4 lb. If the ball is dropped into a swimming pool, it will have neutral buoyancy, just hanging there at whatever height below the surface.

Now if you apply a force to it, ignoring drag it will accelerate in accordance with Newton's Second Law of Motion. (force equals mass times acceleration) Since it's just hanging there in mid-water so to speak, with no other net force being applied, what difference does it make in solving that equation whether it is pushed up, down or sideways?

[mag2555]

The effect of a piston receding on the Intake stroke with the valve open and then air piling in at 14.7 psi for example at sea level is a much stronger factor then gravity when dealing with port runners of the lenght your taking about!

[Tuner]

The point is, gravity doesn't disappear, it is always there and part of the process and any vertical acceleration, up or down, will be plus or minus 1 g. 75 lbs. lifted 1 foot represents 75 foot pounds of force, and the opposite is true if it is dropped or falls or is pulled down. The 1 g is always there, one way or the other.

[n2omike]

The point is, gravity doesn't disappear, it is always there and part of the process and any vertical acceleration, up or down, will be plus or minus 1 g. 75 lbs. lifted 1 foot represents 75 foot pounds of force, and the opposite is true if it is dropped or falls or is pulled down. The 1 g is always there, one way or the other.

Disagree.

Look at the water filled beachball scenario: When the ball is in the pool, it does not sink nor float. It's called neutral buoyancy, and will take an equal force to accelerate it either up OR down. Believe it or not, this buoyancy is powered by gravity. The fact that it is neutral, is because the water in the pool is affected exactly the same as the water in the beach ball. Neither is pulled harder than the other.

The air in the atmosphere and the air going through the carb works the exact same way. Neither air sample is accelerating toward the ground, because of neutral buoyancy. A hot air balloon does not rise until the air inside it is heated to a lower density than the air around it. Air about to go through a carb does not care if it is being accelerated up or down.

[Tuner]

The point is, gravity doesn't disappear, it is always there and part of the process and any vertical acceleration, up or down, will be plus or minus 1 g. 75 lbs. lifted 1 foot represents 75 foot pounds of force, and the opposite is true if it is dropped or falls or is pulled down. The 1 g is always there, one way or the other.

Disagree.

Look at the water filled beachball scenario: When the ball is in the pool, it does not sink nor float. It's called neutral buoyancy, and will take an equal force to accelerate it either up OR down. Believe it or not, this buoyancy is powered by gravity. The fact that it is neutral, is because the water in the pool is affected exactly the same as the water in the beach ball. Neither is pulled harder than the other.

The air in the atmosphere and the air going through the carb works the exact same way. Neither air sample is accelerating toward the ground, because of neutral buoyancy. A hot air balloon does not rise until the air inside it is heated to a lower density than the air around it. Air about to go through a carb does not care if it is being accelerated up or down.

To accelerate the ball in the water from zero to 300 fps in 18 inches, which direction will be easier, down or up? Do you think Earth's gravity has no effect?

[MadBill]

1. There is NO difference, up, down or sideways. Newton's Second Law does not have a term for gravity. It is a well-tested theorem, exemplified in uncountable examples.
2. Yes, No effect in such a circumstance. If the beachball in the example was being supported in the air by a strong man, he would have to exert 261# of force to keep it in position. To accelerate it at a given rate in any direction would require the same additional force.

[n2omike]

To accelerate the ball in the water from zero to 300 fps in 18 inches, which direction will be easier, down or up? Do you think Earth's gravity has no effect?

The definition of a fluid is something that can flow. Gases and liquids are both considered to be fluid, and behave largely the same when it comes to flow. The only difference is viscosity, and the fact that gases are compressible.

Anyhow, when it comes to gravity, it's a wash.
Picture the filled beach ball in the water... For the water in the ball to move down, and equal volume of water needs to be displaced upwards. That's why it has a neutral buoyancy. The same applies for the air. Something that is neutrally buoyant does not accelerate in one direction easier than another.

[Tuner]

To accelerate the ball in the water from zero to 300 fps in 18 inches, which direction will be easier, down or up? Do you think Earth's gravity has no effect?

The definition of a fluid is something that can flow. Gases and liquids are both considered to be fluid, and behave largely the same when it comes to flow. The only difference is viscosity, and the fact that gases are compressible.

Anyhow, when it comes to gravity, it's a wash.
Picture the filled beach ball in the water... For the water in the ball to move down, and equal volume of water needs to be displaced upwards. That's why it has a neutral buoyancy. The same applies for the air.

Something that is neutrally buoyant does not accelerate in one direction easier than another.

.... unless a force is applied. Gravity is a constant acceleration force that is always in the same direction, what we call "down". When something accelerates in the direction we call "down" the 1 G is there for free. When something is accelerated "up" the constant 1G must be overcome. In other words, to accelerate down at a rate of 100 G only requires an applied force of 99 G. To accelerate up at a rate of 100 G requires an applied force of 101 G. Gravity is always present and cannot be ignored.

[CharlieB53]

Gravity has minimal if any effect on air movement.

Pressure differentials cause air movement.

Heating/cooling air causing expansion or contraction .

Piston movement in the bore creates low pressure, the differential pressures the surrounding air attempts to fill that low pressure area.

Granted gravity is the root cause of measured air pressure however as stated fluid dynamics dictates flows.

[Tuner]

Is the fact that a typical Tunnel ram uses gravity more effectively then any other NA manifold give it an inherent notable advantage?

I guess vertical IR stacks might share also share the same advantage regarding gravity.

This is the OP's question. ^^^ The answer is … yes.

[j-c-c]

Got a number of different viewpoints here.

So my takeaway at this point, if one had theoretically a beach ball of zero mass, filled with air, situated in a per vacuum, it would fall "down" with the force of 1g, and if one wanted it to move upwards at that same rate, it would require 2g's of force, just to be very simplistic. Correct?
Down being better.

[n2omike]

.... unless a force is applied. Gravity is a constant acceleration force that is always in the same direction, what we call "down". When something accelerates in the direction we call "down" the 1 G is there for free. When something is accelerated "up" the constant 1G must be overcome. In other words, to accelerate down at a rate of 100 G only requires an applied force of 99 G. To accelerate up at a rate of 100 G requires an applied force of 101 G. Gravity is always present and cannot be ignored.

You're not going to admit it... but you are indeed wrong on this one.

Neutrally buoyant is basically like being in outer space without gravity. There is no real 'up' and 'down' as there is no net gravitational force. With the beach ball, the surrounding water is pushing it up with a force equal to the gravitational force pulling it down. The same goes for a portion of air that is neutrally buoyant in the atmosphere.

I'm sure you know more about carburetors than I do, and I would probably not seriously challenge you in your ballpark. But, this is more of my little corner of the world, and Newtonian Physics is really neat once one purges their selves of some preconceived notions.

[cardo0]

Too much science, way too much and for fluids you should be using Bernoulli's equations in the first place. You will find the gravitational constant is used at least once for variables in Bernoulli's. Well that was for incompressable fluids but since we are really talking compressible fluids we need to use calculas to calculate pressure and pressure losses but Bernoulli has formula using calculas for that also and yes the gravitational constant is included in that one to.

Myself I don't need a course in fluid mechanics to see how a straight shot to the valve helps cylinder filling. Just look at evolution from 23 degree heads to 18 degrees (or less). Hey if flow path didn't matter we would all be racing flatheads.

[naukkis79]

.... unless a force is applied. Gravity is a constant acceleration force that is always in the same direction, what we call "down". When something accelerates in the direction we call "down" the 1 G is there for free. When something is accelerated "up" the constant 1G must be overcome. In other words, to accelerate down at a rate of 100 G only requires an applied force of 99 G. To accelerate up at a rate of 100 G requires an applied force of 101 G. Gravity is always present and cannot be ignored.

Gas molecule isn't standing, it is always constantly moving in all directions at its max speed hitting other molecules and bouncing back. Gas flow is directing those gas movement, when there's enough vacuum on the other side those gas molecules movement isn't anymore to all directions but only to one, towards vacuum as gas molecule isn't hitting others in that direction and so not bouncing back. When all movement is to one direction gas flow is at it's max speed which is also speed of sound in that fluid.

And direction of gas flow is only relative to those pressure differentials, speed of gas molecule is constant.

[n2omike]

Too much science, way too much and for fluids you should be using Bernoulli's equations in the first place. You will find the gravitational constant is used at least once for variables in Bernoulli's. Well that was for incompressable fluids but since we are really talking compressible fluids we need to use calculas to calculate pressure and pressure losses but Bernoulli has formula using calculas for that also and yes the gravitational constant is included in that one to.

Myself I don't need a course in fluid mechanics to see how a straight shot to the valve helps cylinder filling. Just look at evolution from 23 degree heads to 18 degrees (or less). Hey if flow path didn't matter we would all be racing flatheads.

The gravitational constant is not used for 'direction'. The gravitational constant is used with gases to help determine their density.

And, yes... looking down the carburetor and seeing a straight shot at the valve does indeed pay dividends. Tunnel rams will always have their place with the folks who have the balls to use them.