Abstract
Turbulent flow will be the subject of research during this period and near future and hundreds of papers and articles are being published every year.
In this chapter, we emphasize on the physics side of turbulent flow with the engineering application, nature of turbulent, methods on analysis, diffusivity of turbulence, length scales in turbulent flows, energy and vorticity and their relation with length scale.
Diffusive and convective length scales and their relation with boundary thickness at the laminar and turbulent region and a comparison between them are presented in details.
Keywords: Diffusivity, Energy and vorticity, Length scales, Nature of turbulent.