# Underwater forces

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Hi, I'm working on simulating objects behavior underwater. So far here's what I have:

Buoyancy. Upward force that's equal to the displaced water. This would determine if objects float or not. I have no idea yet on how to implement this but I'll figure it out in the next few days. It could be as complex as having different fields for each object or as simple as an flipped gravity.

Pressure? I still haven't got a solid grasp on this idea. So far, I know pressure is a force that acts on the object to all directions. That force magnitude is greater in depth.

Viscous is similar to friction or a force that resist movement.

I have yet to read a material that mentions movement of water in underwater. Is it as simple as wind?

Here's a run down

Gravity

Buoyancy - upward force/upward gravity

Pressure - clueless

Viscous - Drag/Turbulence/Noise field

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A more specific question will increase your chances to a response. Are you trying to build a fluid solver from scratch?

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I apologize if I was vague.

I'm trying to simulate objects underwater with using a fluid solver. I only intend to use forces.

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You probably don't need to simulate the "Pressure force" because it affects the body in any direction so the resulting force is more or less 0.

Actually what you call Buoyancy force is the effect of the difference of the pressure on the top and the bottom of the body. But you probably even don't need it too. Just make Gravity less then at the air.

The effect of viscosity can be easily simulated by Drag force. As I understand the Drag force is just proportional to the velocity in DOPs. But in reality as I remember the Drag force is proportional to the sqr(v). And viscosity in addition is another force that is proportional to v.

And if you have any flow of the water just add that custom force ad noise.

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