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# 2D Computational Fluid Dynamics Simulation of a bullet inside a fluid

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This is the closest simulation I have found to the frontal shot.

We can clearly see how the practical diameter of the "bullet" grows to the size of a baseball, fist or grapefruit.

BTW: It is easy to prove the impossibility of the Jet Effect, which explains being abandoned by the WCR apologists.

-Ramon

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Ramon,

The computer-generated depiction of a bullet's flight through air (or some other fluid) appears to me to be over-simplified.

When a bullet leaves the barrel of a gun, it follows a path that curves, ultimately into some object. The default object is the Earth. The path is a parabola. The parabolic nature of the curve is caused by the force of gravity, a downward-directed force. The shape of the curve in one projection (wide or narrow) is determined by the "headwind" the bullet encounters (frictional force). In another projection, the bullet moves to the right or left depending upon the force exerted by wind blowing from left to right. This description comes from Newtonian physics. Specifically, Newton's Second Law, F = ma.

The computer-generated depiction you present may describe accurately the airflow in the wake of a bullet traveling through air. I don't know. The projection onto my computer screen is inaccurate, however, because it does not reflect frictional force acting upon the bullet.

The jet effect is real, but Luis Alverez got it wrong in my opinion. When a bullet enters a hard object filled with fluid, two things happen. First, the momentum of the bullet is transferred to the object (to the extent the bullet doesn't exit the object with such-and-such a mass and such-a-such a velocity). Second to the extent momentum is transferred to the object, energy is also transferred to the object. So, a bullet entering a skull transfers energy to fluid and other matter within the skull. If the energized fluid and other matter exits the bullet hole, as it exits it exerts a force backward against the object, equal to the energy of the ejection.

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The jet effect is real, but Luis Alvarez got it wrong in my opinion.

Sure it is, Jon. Provided that you use melons of a very precise variety, diameter, ripeness, bound by scotch tape.

If you try it with any other scenario: say, coconuts, it fails miserably.

Dr. Alvarez himself was ashamed (*), and I -as a fellow Hispanic who used to be proud of his dinosaur extinction discovery- am profoundly disappointed at him.

-Ramon

(*) Maybe "cautious", "hesitant", "apologetic" are better terms.

Edited by Ramon F. Herrera
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Jon:

The following fact is the Jet Effect killer. In order for it to work the entry hole must be round, small, of about the same diameter as that of the projectile. The rest of the "melon" must remain sealed before the explosion. The exit hole cannot be too large, either. We are talking a contained bomb here.

Does this scenario look to you like matching the requirements?

-Ramon

Edited by Ramon F. Herrera
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• 2 weeks later...

Ramon,

The computer-generated depiction of a bullet's flight through air (or some other fluid) appears to me to be over-simplified.

By design! Do you know the cost (in computer resources and actual dollars) of those simulations? The challenge of the researchers is to capture the essence.

-RFH

Edited by Ramon F. Herrera
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Ramon,

The projection onto my computer screen is inaccurate, however, because it does not reflect frictional force acting upon the bullet.

The friction is color coded. A current unknown of my model is whether such friction can completely vaporize the copper in such short distance, or to what extent.

For a more discriminating use of color to depict different fields, see here:

-Ramon