Final answer:
Whether fluid flow is laminar or turbulent is determined by velocity and viscosity. Laminar flow features smooth, orderly motion in layers, while turbulent flow is characterized by irregular, mixing paths. The Reynolds number is used to predict the type of flow based on these properties.
Step-by-step explanation:
The factors that determine whether a fluid flow is laminar or turbulent are primarily velocity and viscosity.
Laminar flow is characterized by the smooth, orderly movement of fluid particles in layers, without mixing between the layers, which occurs due to the viscous drag between them.
Turbulent flow, on the other hand, occurs when the fluid moves in irregular paths, causing mixing and swirling due to disturbances or high flow velocities overcoming the dampening effect of viscosity.
The onset of turbulence can be predicted by a dimensionless number known as the Reynolds number, which incorporates the fluid's velocity, density, and viscosity, as well as the characteristic length scale of the flow situation. A low Reynolds number indicates laminar flow, while a high Reynolds number indicates turbulent flow.