Non-stationary viscous flow around of two spheres

The problem of non-stationary viscous flow around of two spheres is considered. Hydrodynamic interaction of particles is taken into account. The solution of problem was obtained in terms of small parameter. The forces and torques exerting on spheres are calculated. Results were used for analysis of possibility to obtain the expressions for average force and torque in mixture in terms of volume concentration of hight degree. The general solution of problem for viscous flow around more than two spheres is given.