Water speed and bullet penetration

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Discussion Overview

The discussion centers around the effect of water speed on a bullet's ability to penetrate water, exploring both theoretical and practical implications. Participants consider various aspects of bullet dynamics in water, including the impact of water flow and the physics of penetration.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions whether the speed of water affects a bullet's penetration ability, noting that low caliber bullets can penetrate water to a depth of over 3 feet in still water.
  • Another participant suggests that the speed of water would influence the bullet's trajectory and speed due to changes in friction, depending on the relative motion of the bullet and water.
  • A different viewpoint emphasizes that the bulk flow of water could deflect the bullet off course, particularly if the shooter is firing upstream, potentially reducing penetration.
  • Concerns about refraction effects when shooting at targets underwater are raised, indicating that this could complicate the bullet's path.
  • One participant argues that if the water speed is negligible compared to the bullet's speed, its effect can be ignored, except in extreme cases like shooting against a waterfall.

Areas of Agreement / Disagreement

Participants express varying opinions on the significance of water speed in relation to bullet penetration, with no consensus reached on the extent of its impact. Some participants agree that water speed may have an effect, while others suggest it can be negligible under certain conditions.

Contextual Notes

The discussion includes assumptions about the conditions under which bullets are fired and the nature of water flow, which may not be fully explored. There are also references to physical concepts like refraction and diffraction that are not elaborated upon.

Who May Find This Useful

Writers and creators interested in realistic portrayals of physics in action, particularly in scenarios involving projectiles and fluid dynamics, may find this discussion beneficial.

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This may be an odd question but I am wondering if water speed affects a bullet's ability to penetrate water.

Pardon my lack of knowledge, but I am aware that low caliber bullets can penetrate water past 3ft (Thank you Mythbusters). However, the tests they completed were all based around a pool full of water not running water, such as a river or dam. If I my understanding is correct, it is the density of water that causes the bullet to slow down, but does water speed affect this as well? Or would adding water speed the equation only effect the accuracy and not so much the speed of the bullet? I would assume that if water speed would indeed assist in slowing a bullet it would have to be a considerable amount of force in order to do so.

Just to be clear I am a writer who is looking for some clarification for a potential event in a story, so mathematical calculations for my benefit aren't necessary. I would, however, appreciate some details so that the story can be accurate. There's just something fun about writing an interesting scenario that sounds far fetched but that could actually happen. Thank you in advance.
 
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I think that the speed of water would effect the bullet too.
Because if the water is stand still and the bullet move the water is move too (from the bullet view).
So if the water is move so it speed would increase or reduce (from the bullet view) make the friction would increase or reduce make the bullet speed increase or reduce.
My literature suck :frown:
 
The bulk flow of the water will knock the bullet off course in the direction of the flow - think of the water as a whole lots of little particles hitting the bullet... if the flow was towards the gunman, Like if he is in a boat on a river and firing upstream from low down, then it could mean that the bullet penetrates less.

If your gunnman is firing at a target under water there is probably a bigger effect due to refraction.
 
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Wow that is much more easy to understand :oldbiggrin:
 
Simon Bridge said:
due to diffraction.
refraction?
 
As long as the speed of water is negligible compared to the speed of the bullet, it can be ignored.
Maybe if you were shooting up against a waterfall, the effect would be noticeable, otherwise likely not.
 
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Quantum Velocity said:
Wow that is much more easy to understand :oldbiggrin:
replace "more easy" with "easier" :D
it's practise ... I was mostly saying what you said.
 
What ever
 
Thank you for the replies. I appreciate the comments and explanations. This points me in the right direction. ^^
 
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