Two-liquid model for description of flows in tubes of circle profile is presented. This model explains well-known experimental fact which consists of growth (approximately in 2 degrees) of critical Reynolds number at which transfer to turbulent regime takes place in comparison with tubes of other profiles. A special characteristic of this model is a set of vortices which separates flow from walls of tube. An electromagnetic analogy with infinitely long solenoid is used for determination of flows’ parameters.