Abstract:The fundamental aspects of isotropic turbulence are reviewed in reviewed in order to gain a betterinsight into the physical processes of turbulence. After first reviewing the Kolmogorov energyspectrum and the energy cascade, the Kolmogorov hypothesis of local isotropy is discussed in depth.Then, the detailed physical processes involving energy transfer and interacting scales in isotropicturbulence, including triad interactions, are reviewed. The inertial range and self-similarity are alsodiscussed along wi...