Enhanced heat transfer in fluids by high-frequency oscillations within a capillary bundle is a new interesting phenomenon. A new method to describe this phenomenon has been developed. Authors have obtained the same dimensionless expression by means of three different methods, experimental data analysis,dimensionless analysis of differential equations and transformation of laminar hydrodynamic theoretical expression. It shows that the ratio of the effective thermal conductivities to normal conductivities of fluids is proportional to a certain power of Prandtle number, second power of the ratio of tidal displacement to capillary radius and nearly first power of Womersley number. This dimensionless expression is convenient for calculating and experimenting.