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 comprising:
obtaining data defining a porous medium, data defining a fluid, and user adjustable parameter values;
determining a first volume fraction for the porous medium, and a second volume fraction for the fluid;
obtaining fluid parameter values;
determining velocities of a plurality of objects representing the porous medium using the fluid parameter values,
wherein the velocities of the plurality of objects are determined using only a particle-based solver for the plurality of objects, and the fluid parameter values are determined using only a different, grid-based solver for the fluid, and wherein the plurality of objects is iteratively coupled to the fluid
wherein the iterative coupling comprises Newtonian iteration of the particle-based solver and the grid-based solver for:
a specified number or iterations, or
until a pressure change or velocity change per iteration falls below a threshold value; and
sending motion parameters to an animation creation system, the motion parameters based on the velocities of the plurality of objects and the fluid parameter values.
2. The method of claim 1 , wherein the fluid parameter values include fluid velocity values and pore pressures.
3. The method of claim 1 , wherein each of the velocity values for the plurality of objects is solved by using fixed fluid velocity values and fixed pore pressures based on locations within the fluid.
4. The method of claim 3 , wherein the grid-based solver for the fluid is configured to solve a system of equations to obtain the pore pressures and the fluid velocity values.
5. The method of claim 1 , wherein the objects of the plurality of objects are independently movable with respect to one another.
6. 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.
7. The method of claim 1 , wherein determining velocities of the plurality of objects comprises using buoyancy and drag forces to determine relative motion of the plurality of objects and the fluid.
8. The method of claim 7 , wherein the drag forces being used to determine relative motion of the objects and the fluid comprise a quadratic drag force term.
9. The method of claim 1 , wherein the porous medium comprises cloth, bubbles, sand, hair, foam, sponge, or plants.