Numerical implementations of an iterative method with boundary condition splitting as applied to the nonstationary stokes problem in the gap between coaxial cylinders

Numerical implementations of a new fast-converging iterative method with boundary condition splitting are constructed for solving the Dirichlet initial-boundary value problem for the nonstationary Stokes system in the gap between two coaxial cylinders. The problem is assumed to be axially symmetric and periodic along the cylinders. The construction is based on finite-difference approximations in time and bilinear finite-element approximations in a cylindrical coordinate system. A numerical study has revealed that the iterative methods constructed have fairly high convergence rates that do not degrade with decreasing viscosity (the error is reduced by approximately 7 times per iteration step). Moreover, the methods are second-order accurate with respect to the mesh size in the max norm for both velocity and pressure.