Quick laminar - The highly ordered fluid motion characterized by smooth layers of fluid is called laminar.
transitional - A flow that alternates between being laminar and turbulent is called transitional.
turbulent - The highly disordered fluid motion that typically occurs at high velocities and is characterized by velocity fluctuations is called turbulent.
Details
Some flows are smooth and orderly while others are rather chaotic. The highly ordered fluid motion characterized by smooth layers of fluid is called laminar. The word laminar comes from the movement of adjacent fluid particles together in "laminates." The flow of high-viscosity fluids such as oils at low velocities is typically laminar. The highly disordered fluid motion that typically occurs at high velocities and is characterized by velocity fluctuations is called turbulent. The flow of low-viscosity fluids such as air at high velocities is typically turbulent. The flow regime greatly influences the required power for pumping. A flow that alternates between being laminar and turbulent is called transitional. The Reynolds number is the key parameter for the determination of the flow regime in pipes.
Moderate Re implies a smoothly varying laminar flow. High Re indicates turbulent flow, which is slowly varying in the time-mean but has superimposed strong random high-frequency fluctuations.