Textbook in PDF format An original method of investigation of the conjugate conductive-convective problem of periodic heat transfer is developed. The novelty of the approach is that a particular conjugate problem is replaced by a general boundary-value problem for the heat conduction equation in the solid. Within the framework of the hyperbolic model of thermal conductivity, the effect of self-reinforcement of the degree of conjugation by increasing the period of oscillations is found. The processes of hydrodynamics and heat exchange with periodic internal structure are considered: periodic model of turbulent heat transfer, hydrodynamic instability, bubbles dynamics in liquid, and model of evaporating meniscus. The book is intended as a source and reference work for researchers and graduate students interested in the field of conjugate heat transfer