Final answer:
Fluid flow characteristics include flow rate, velocity vectors, and the type of flow—laminar or turbulent—often determined by the Reynolds number. Pressure difference drives flow, with fluid moving from high to low-pressure areas, affecting flow rate. Turbulent flow involves mixing layers of fluid through eddies and swirls.
Step-by-step explanation:
Characteristics of Fluid Flow
Understanding the characteristics of flow in fluids involves analyzing aspects such as flow rate, velocity vectors, and the nature of the flow—whether it is laminar or turbulent. In particular, when discussing laminar versus turbulent flow, reference is often made to the dimensionless Reynolds number (NR), defined as NR = 2pvr, where ℓ is a characteristic length, p the fluid density, n its viscosity, and u the object's speed in the fluid. Laminar flow occurs when NR is below about 2000, characterized by smooth and orderly fluid motion. Turbulent flow is indicated by NR above 3000, where eddies and swirls cause mixing of fluid layers. The state of flow between NR of 2000 and 3000 is transitional and can exhibit characteristics of both laminar and turbulent flow.
The equation of continuity relates flow rate Q to the cross-sectional area A and the velocity u as Q = Au, underlining that for an incompressible fluid, the mass entering a pipe must equal the mass exiting it. This fundamental principle assists in predicting how fluids behave when subjected to varying pressures and cross-sectional areas across different segments of a system.
Pressure differences are the primary causes of flow, with fluid moving from regions of higher pressure to those of lower pressure. The magnitude of this pressure differential directly influences the flow rate. Turbulence can be affected by the surface roughness of objects in the fluid and can manifest with a turbulent wake behind objects or with some flow remaining laminar over the object's surface.