ABSTRACT
Fluids deform continuously as long as the fluid stress exceeds the viscosity or internal resistance of fluid molecules to deformation, producing laminar and turbulent flows with transitions in between. Laminar flow occurs at high viscous forces accompanying low velocity and small depth of flow, such that neighboring fluid layers move smoothly past each other without mixing. The flow becomes unstable or turbulent when velocity increases in the flow of a fixed size. Turbulent flow comprises unstable eddy motions, which rapidly dissipate kinetic energy in the flow, thoroughly distribute the shear stress in the medium, and increase the resistance to flow.
