The motion of an elastoplastic medium in a circular tube heated due to boundary friction

The solution of a sequence of related problems in thermoelastoplasticity, concerning the origin and development of the flow of a medium in a cylindrical tube with a varying pressure drop and heating of the material due to friction at the tube wall with the subsequent flow deceleration when the load is slowly removed and the layer material cools off, is presented. The thermophysical and deformation processes are interconnected when the yield stress is temperature dependent. The conditions for the generation of a viscoplastic flow and the relations for the advancement of the elastoplastic boundaries through the layer are indicated, and the flow rates and both irreversible and reversible large deformations are calculated.