Particulate Flow Simulation

Six settling disks in an Oldroyd-B fluid:

Six sedimenting disks form a long chain after drafting, kissing and chaining, which is different from the well known phenomenon called drafting, kissing and tumbling for disks settling in Newtonian fluid.

The dimension of computational domain = (0,1)x(0,7) initially, then it moves vertically with the center of the lowest disk.
The radii of the disks are 0.125.
The density of disks = 1.01
The density of fluid = 1
The viscosity = 0.26
The relaxation time = 1.3
The retardation time = 1.3/8
The mesh size for the velocity field = 1/96
The mesh size for the extra stress tensor = 1/96
The mesh size for the pressure = 1/48
The time step=0.0004
The averaged terminal speed =0.1535
The particle Reynolds number = 0.1476 < 1
The Mack number = 0.3432 < 1
The Debra number = 0.7981
The elasticity number = 5.408