Help with a research article!

[Stavi300RUM]

Hello! Kind of a weird and not so normal question, but I am in need of some help with a research article relating to fluid dynamics. I chose bullet drag. I do understand the basics such as air and gravity being a constant external force, but I want to know if the time the bullet is in the barrel causes drag on the bullet along with how the spin does.

Hope this makes sense.

Thanks all!

 

[RockyMtnMT]

Not sure what you mean by how long the bullet is in the barrel.

Steve

 

[PGJPJ]

Hmmm, it's been a long time since college

But obviously there would be a drag force inside the barrel. Its modeled the same as what you are calling 'air' drag. It would just have a different coefficient of drag force. Also, inside the barrel would be the normal force, equal and opposite of the force of gravity (equal, because there is no acceleration in the Y-axis till the bullet leaves the barrel). There is an angular acceleration due to the spin of the bullet, so there would be a resultant force associated with that. but sorry, it's just been too long to remember how to model the effects of that force.

The most important thing to remember… there was this dude who sat under an apple tree. One day, an apple fell and hit him on the head, and that's when he figured out that the sum of the forces equals mass times acceleration.

 

[Stavi300RUM]

Hmmm, it's been a long time since college

But obviously there would be a drag force inside the barrel. Its modeled the same as what you are calling 'air' drag. It would just have a different coefficient of drag force. Also, inside the barrel would be the normal force, equal and opposite of the force of gravity (equal, because there is no acceleration in the Y-axis till the bullet leaves the barrel). There is an angular acceleration due to the spin of the bullet, so there would be a resultant force associated with that. but sorry, it's just been too long to remember how to model the effects of that force.

The most important thing to remember… there was this dude who sat under an apple tree. One day, an apple fell and hit him on the head, and that's when he figured out that the sum of the forces equals mass times acceleration.

That's the same idea I'm going with this. I'll have to try and find more info on this and go from there!
Thank you for the ideas!

 

[RockyMtnMT]

The friction between the bullet and the barrel will cause pressure as the powder burns. As long as the powder is burning the velocity will increase along with the pressure. If the pressure drops the bullet will decelerate because of friction or drag inside the barrel. Generally speaking a bullet would increase velocity for the entire time it is inside the barrel, unless the barrel is so long that the powder is burned out before the bullet exits.

Maybe I am missing something.

Steve

 

[kimberyote]

Hello! Kind of a weird and not so normal question, but I am in need of some help with a research article relating to fluid dynamics. I chose bullet drag. I do understand the basics such as air and gravity being a constant external force, but I want to know if the time the bullet is in the barrel causes drag on the bullet along with how the spin does.

Hope this makes sense.

Thanks all!

Dr. Robert Rinker might be your man.