This course is aimed to provide an overview of the fundamental physical processes in large Reynolds number turbulent flows. Topics include review of tensors, probabilistic tools, and conservation laws. Free shear flows: turbulent kinetic energy transport and dissipation. Scales of turbulent motion: Kolmogorov hypothesis, structure functions, Kármán-Howarth equation, 4/5th law, Fourier modes, Kolmogorov-Obukhov spectrum, intermittency, and refined similarity hypothesis. Turbulent mixing: scalar transport and dissipation. Alignments of vorticity, scalar gradient, and strain rates. Diagnostics in turbulent flows.