Staggered grid (sedimentation of solid particles)
 

Hi,

I am writing my first own DNS program for sedimentation. I have used a finite-difference method for solving the two-dimensional incompressible time-dependent non-linear Navier-Stokes equations, which were discretized using a staggered grid in space domain.

Can I use the same staggered grids in space for spherical solid particles of sediment?

What are the features of the boundary conditions? If I want to use staggered grids, should I use the conditions similar to the condition on the lid in the lid-driven cavity problem, where u[i][N+1]=2*u0-u[i][N], i.e. can I use something like that on the border solid particle-fluid?
u[i][j+1]=2*U[i][j]-u[i][j],
v[i][j+1]=2*V[i][j]-v[i][j], where U and V are the components of the particle velocity, u and v are the components of the fluid velocity.

Should I take into account that the particle rotation is equal to fluid vorticity at the boundary? I want to do calculation for small and high Re numbers.

Can I take into account only the change of sediment particle motion direction near the borders (walls) of rectangular cavity and leave the angular velocity of a rotating sediment particle without changing or not?

Thank you in advance for answers.