Numerical Simulation Study on Flow and Fracture of Granular Materials

Algorithm 1

Mesh generation algorithm for the particle system.

(1)	Transfer information about particle size and position in granular system obtained from initial configuration algorithm.
(2)	Generate a particle at the origin of the coordinate system. The radius of the particle can be taken as the radius of any particle in the granular system.
(3)	Start the mesh generation algorithm, discretize the particle with tetrahedron elements, and record the basic information of each tetrahedron, including the coordinates of tetrahedron vertices, which vertices make up each edge, each surface, etc.
(4)	Cycle all particles in the granular system.
	(a) Translate the spherical center of the particle to the position of the spherical center of a particle in the granular system.
	(b) Enlarge or reduce all tetrahedrons according to the ratio of two particle diameters.
	(c) Rotate all tetrahedrons according to random rotation axis and rotation angle.
	(d) Update the basic information of tetrahedrons.
(5)	End the cycle.
(6)	Generate a directory and store all the basic information of tetrahedron in the directory.