Solution of convection problem in a rotating tube by the Fourier method

The non-stationary boundary value problem on the motion of a fluid in a rotating cylindrical pipe is studied in this paper,. The Oberbeck-Boussinesq equations are used to describe the motion of a fluid. From a mathematical point of view, the problem is inverse with respect to pressure gradient along the axis of the cylinder. The solution is found with the use of the method of separation of variables in the form of special Fourier series. Sufficient conditions are given for the solution of a non-stationary problem to reach a stationary regime with increasing time.