3 ms·
Can someone explain what kind of fluid this is simulating? Obviously it implements the general Navier-Stokes fluid equations, but if I twirl some ink in a cup o
by gyomu 2y ago
Can someone explain what kind of fluid this is simulating? Obviously it implements the general Navier-Stokes fluid equations, but if I twirl some ink in a cup of water it looks nothing like this so I'm confused by the naming.
Is it a scale issue? When I look at the sea it doesn't look much like this either, so I don't think so?
Is there a combination of parameters I could set in the simulation such that it looks like what I see when I pour myself a glass of water, or watch waves at the beach?
Or is it because all the real world examples I'm referencing are 3D, and this is 2d?
- hwillis 2y agoIt should look basically accurate, except that the edges absorb momentum. You're looking downward into a pool of water and dragging the mouse is like dragging a finger through the water. Not totally the same, because the mouse is directly imparting momentum into the fluid instead of displacing it- that's why twirling looks wrong. If you move the mouse in a circle it will constantly grab and pull back the fluid, which can't be done in real life. The fluid has a set lifetime instead of actually mixing, which makes it look different- normally the edges would dissipate faster than the areas that are all ink but instead it just all fades at the same rate. The simulation is kind of 3d- since it's incompressible, pressure at any point is proportional to the height of the fluid. Advection still happens on a single plane, but if the pressure-related height is relatively large compared to the average depth of the fluid it's not a bad approximation. The viscous losses are also kind of arbitrary, but it's not far from water.