Not knowing anything about Bernoulli's equation, etc., I searched the Internet out of curiosity and found the following:

This source said that:

quote:

Bernoulli's equation is one of the most famous equations of fluid mechanics and is applied to a lot of different situations. Unfortunately, it is also applied in situations where it does not belong. Give some people a nice and clean equation and they want to stretch it beyond its limits. Bernoulli's equation is basically defining a relationship between the pressure and the fluid velocity. The velocity is an unambiguious concept but pressure is a bit confusing, specially when people talk about static pressure and stagnation pressure, etc.

It is then concluded that:

quote:

Therefore:
For an inviscid incompressible fluid with negligible body force the stagnation pressure is equivalent to the sum of the dynamic pressure and the static pressure, and is constant throughout the fluid.

Please note that we have put 3 important conditions on this statement:

1. The flow must be inviscid (non-viscous)
2. The Flow must be incompressible
3. Negligible body force

Bernoulli equation can be used to study flow from a tank through a small orifice, trajectory of a free jet, flow distribution in a closed channel, etc. People have used it to explain other physical situations.

In another source I found this part very interesting:

quote:

2. Misinterpretations and misapplications of Bernoulli's law

2.1 Static pressure in a free air stream

Static pressure is the pressure inside the stream measured by a manometer moving with the flow. At the same time, the static pressure is the pressure which is excerted on a plane parallel to the flow. Thus the static pressure within an air stream has to be measured carefully using a special probe. A thin disk must cover the probe except for the opening. The disk must be positioned parallel to the streaming flow, so that the flow is not interfered with.

If the static pressure is measured in the way outlined above within a free air stream generated by a fan or a hair dryer it can be shown that the static pressure is the same as in the surrounding atmosphere. Bernoulli's law cannot be applied to a free air stream because friction plays an important role. It may be noted that the situation is similar to the laminar flow of a liquid with viscosity inside a tube. The different velocity of the stream layers is caused by viscosity. The static pressure is the same throughout the whole cross-section. A free air stream in the atmosphere is exlusively decelerated by friction. If static pressure in a free air stream is equal to atmospheric pressure, some of the striking lecture demonstrations are interpreted incorrectly since the effects observed are not caused by Bernoulli's law.

Re this cursive printed paragraph: true or false?

As I've said before

quote:

.... I leave with all due respect for yourself and all the other experts to investigate and come up with a valid solution to all that is to it.

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Chris,

quote:

Alf posed the question on page 9 of "ongoing discussion

And that is where it will be answered. Are you so paranoid that you have to follow me around the forum with your "questions"? I have made a post in the Dogs forum, why not go there and ask it there as well? This thread is hosted by Jagter and is about Mauritz' ridiculous theory that rotational energy is significant in solid bullet terminal performance. Now there is a topic worthy of your paranoid attention. Of course you will ignore that because Mauritz is your buddy and colleague and the two of you agree on all things ballistic.

You wade in here with lies (Gerard claims that he has the calculations) and snide remarks (State secret, my ass) and a demonstrated level of ignorance (stagnation force) and then expect to be treated with civility. You are indeed a ballistic buffoon.

Alf,
I have been looking at the field results of different SP and SF relationships for years and, although there is a clear connection, it never occurred to me to draw the conclusion through polar and transverse moments of inertia. Not enough attention paid in math class, I guess. This goes to shoulder stabilisation, not so?

Gerard,

You did say you do not want to share your calculations with me ... apparently I am from the opposition after you have accepted that I am not part of Rhino Bullets (this means that I do not share in their profits and nor do I earn a cent from them)

So if you do not want to SHARE the info, then I must assume it is a STATE SECRET and you have it down to a T !!! (Logical deductive reasoning) Now that we know that no calculations exist, it only proves the point that you will answer any damn thing to bail you out of a tight corner.

Chris Bekker

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Alf,
You seem to be getting at shoulder stabilization now. That makes sense to me. My university physics and fluid mechanics courses (in a chemical engineering/pre-med curriculum) flowed past long ago. I do vaguely recall Mr. Bernoulli. Though I aced the courses and enjoyed them greatly, I must say they have had little relevance to my area of medicine. Nor does calculus. Statistics is most important in day to day considerations of medicine.

Statistical significance is the bane of the Iron Buffalo too. I have to generate a thousand data points for any comparison to hold water around here.

This will require a large staff and a Federal grant.

I propose that I move the Iron Buffalo to the flooded center of New Orleans.

I will find plenty of help for a decent wage there as the city is rebuilt and reopened. Plenty of water available too for easy dipping with a 5 gallon bucket to fill the water bags. Plenty of ply wood lying around down there in New Orleans too, or a pre-cut dry load could be barged in with suitable funding.

Chris,

quote:

Logical deductive reasoning

From you?

Alf,
There is nothing of what you put forward that does not fit in with the practical side and what I have been observing. As long as a bullet is moving fast enough through the medium to generate significant forces, your deductions are reasonable. By fast enough I mean up to the last couple of inches of the wound channel if the bullet does not exit. If the bullet exits, it is unusual to find unexplained deviations and deviations can almost always be explained at the hand of a failed bullet. I have learned a lot and need to dust off my thinking cap.

RIP,
Hi, where ya been? Welcome back anyway.

Hi Gerard,
I am still watching from the peanut gallery when i can.

quote:

Originally posted by Gerard:
I have made a post in the Dogs forum, why not go there and ask it there as well?

Gerard is going to the dogs ... yes ... no?



Chris Bekker

All theories aside. I KNOW that a 480 Woodleigh Solid, from my 450 No2, shot into buff [2] or elephant [ 3, head or body, from 6 yards to 120 yards] will penetrate plenty deep enough.
Do not get me wrong, Testing in various different media is a good thing, but The ultimate data comes from shooting the actual animals.

You "Testers" do not take this as ANY sort of ctiticism. I have done a "little" testing my self over the years.

I find the science called Physics very interesting and the more I read about it, the more questions are coming up in my mind.

With reference to the following then:
Alf in his post above dated 25 August 2005 11:33 -

quote:

The projectile is inert and resists the linear and rotational motion. This inertia causes stresses within the projectile material. When these forces exceed the tensile strength of the projectile material the projectile fails,

this question comes up in my mind:
"Is Inertia Real or Imaginary?"

The above is asked after having read these sentences:

quote:

......the only way an object can ever be caused to accelerate (change its motion) is when an acceleration-causing, action force is present,

and secondly:

quote:

Thus the simple absence of such an action force leaves the object with no other choice but to wait in the inactive state of motion (rest or uniform motion, known as rest-motion) for the next acceleration-causing action force to come along.

Your comments please on the question:
"Is Inertia Real or Imaginary?"

Incompressibility follows from constant density; it suggests for static flows (ie -- non-time varying) that div v = 0 (divergenceless velocity fields). It is a property of the FLUID, and of the flows that the fluid performs. AIR is compressible (a good chunk of the crack of a bullet is supersonic shock, which is a compression effect). Even so, in compressible fluids with turbulent flow, even when Bernoulli's equation does not represent an exact solution, similar pressure effects can be observed. Note the "venturi effect" that made our carburators work all those years (still does, for that matter).

The best discussion of the Bernoulli equation I've seen lately is at: http://user.uni-frankfurt.de/~weltner/Mis6/mis6.html

Dan

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DanEP:
The article you provided a link to above is the same one that I have referred to in the second link on my first post on page 2 above.

In it's high velocity flight through air the bullet certainly compresses the air (even if only temporarily) and that should increase the amount of friction.
Right or wrong?

Alf:

quote:

So in stead of flexing, the back end of the projectile is literally driven into the front part which resists the force.

Alf, this resistance force, isn't it rather caused by friction on the front part while the bullet is travelling through the air at high velocity than the 'inertia' of the bullet?

Please follow the link in the PM I have sent for your attention.

.

Truvelloshooter, and Gerhard, please grow up. You are giving us (South Africans) a bad name.

Jagter,
We must distinguish between the two events of accelleration from rest to a couple of bullet lengths in front of the muzzle, and the rest of the decelerating flight of the bullet to contact with the target. In the first instance there is inertia (or whatever else we could call it), that must be overcome and this is what causes obturation of the bore by the bullet to a lesser or greater extent, depending on construction and material tensile strength. In the second instance we must note that we now deal with retardation forces acting to reduce the Ke of the bullet - a completely different set of circumstances.

I am trying to come to grips with Ethan Skyler but it will take a while longer.

KarlS,
Welcome to AR. With regards to your comment: You will probably be glad to see the reply I posted at this page.

It is today exactly one month (30 days) ago that the following promise was made in a post dated 29 August 2005 22:43 on page 9 of the 'Ongoing discussion - 380gr Rhino' under the 'Big Bores' forum:

quote:

I have been away for five days and could therefore not respond on Jagters posting on the solid bullet article. A complete response will follow.

Kind regards
Dr. Mauritz Coetzee.

One would think that a learned man would apologize when making such an obvious mistake and then use the opportunity to correct himself and restore his credibility.

Sorry Mauritz, you have disgraced yourself by not keeping your promise and will have to live with it for the rest of your days.