Method for simulating fluids interacting with submerged porous materials
A method for generating one or more visual representations of a porous media submerged in a fluid is provided. The method can be performed using a computing device operated by a computer user or artist. The method includes defining a field comprising fluid parameter values for the fluid, the fluid parameter values comprising fluid velocity values and pore pressures. The method includes generating a plurality of particles that model a plurality of objects of the porous media, the plurality of objects being independently movable with respect to one another, determining values of motion parameters based at least in part on the field when the plurality of particles are submerged in the fluid, buoyancy and drag forces being used to determine relative motion of the plurality of particles and the fluid, and generating the one or more visual representations of the plurality of objects submerged in the fluid based on the values of the motion parameters.
1. A computer-implemented method for generating one or more visual representations of a porous medium submerged in a fluid, the computer-implemented method comprising:
defining a field comprising fluid parameter values for the fluid, the fluid parameter values comprising fluid velocity values and pore pressures;
defining a plurality of objects comprising the porous medium at locations within the field; and
determining a first set of motion parameter values for the fluid based at least in part on the field, the first set of motion parameter values simulating fluid motion and determined using only a grid-based solver based on representations of buoyancy forces and representations of drag forces;
determining a second set of motion parameter values for the plurality of objects based at least in part on the field, the second set of motion parameter values simulating motion of objects of the plurality of objects and determined using only a particle-based solver different from the grid-based solver based on the representations of the buoyancy forces and the representations of the drag forces; and
iteratively coupling the plurality of objects to the fluid based on the first set of motion parameter values and the second set of motion parameter values,
wherein the iterative coupling comprises Newtonian iteration of the particle-based solver and the grid-based solver for:
a specified number or iterations per time step, or
until a pressure change or velocity change per iteration falls below a convergence threshold value.
2. The method of claim 1 , wherein the objects of the plurality of objects are independently movable with respect to one another.
3. The method of claim 1 , wherein movement of the objects of the plurality of objects relative to one another is constrained in one, two, or three degrees of freedom.
4. The method of claim 1 , wherein the solver for the fluid is Eulerian and the solver for the plurality of objects is Lagrangian.
5. The method of claim 1 , wherein the solver for the porous medium is configured to solve for a velocity value of each object of the plurality of objects by using fixed values of the fluid velocity and pore pressures at each object's locations within the field.
6. The method of claim 1 , wherein the solver for the fluid is configured to solve a system of equations to obtain the pore pressures and the fluid velocity values of the fluid at locations within the field.
7. The method of claim 1 , wherein the drag forces being used to determine relative motion of the plurality of objects and the fluid comprise a drag force term.
8. The method of claim 1 , wherein defining the pore pressure values and the fluid velocity values includes assigning a velocity to each object of the plurality of objects.
9. The method of claim 8 , wherein the assigned velocity is zero.
10. The method of claim 1 , wherein the porous medium comprises cloth, bubbles, sand, hair, foam, sponge, or plants.
11. The method of claim 1 , wherein the fluid comprises water, air, or oil.
12. The method of claim 1 , further comprising generating one or more visual representations of at least a portion of the plurality of objects.
13. The method of claim 1 , further comprising generating one or more visual representations of at least a portion of the fluid.
14. The method of claim 1 , further comprising generating a time sequence of visual representations at least a portion of the plurality of objects submerged in at least a portion of the fluid.
15. A computer system for generating the one or more visual representations of the porous medium submerged in the fluid, the system comprising:
at least one processor; and
a computer-readable medium storing instructions, which when executed by the at least one processor, causes the system to carry out the method of claim 1 , the method further comprising generating one or more visual representations of the plurality of objects submerged in the fluid based on the values of the motion parameters.
16. A non-transitory computer-readable storage medium storing instructions, which when executed by at least one processor of a computer system, causes the computer system to carry out the method of claim 1 .
17. A non-transitory computer-readable medium carrying instructions, which when executed by at least one processor of a computer system, causes the computer system to carry out the method of claim 1 .