There are in general three types of fluid flow in pipes
Laminar flow generally happens when dealing with small pipes and low flow velocities. Laminar flow can be regarded as a series of liquid cylinders in the pipe, where the innermost parts flow the fastest, and the cylinder touching the pipe isn't moving at all.
In turbulent flow vortices, eddies and wakes make the flow unpredictable. Turbulent flow happens in general at high flow rates and with larger pipes.
Shear stress in a turbulent flow is a function of density - ρ.
Transitional flow is a mixture of laminar and turbulent flow, with turbulence in the center of the pipe, and laminar flow near the edges. Each of these flows behave in different manners in terms of their frictional energy loss while flowing and have different equations that predict their behavior.
Turbulent or laminar flow is determined by the dimensionless Reynolds Number.
The Reynolds number is important in analyzing any type of flow when there is substantial velocity gradient (i.e. shear.) It indicates the relative significance of the viscous effect compared to the inertia effect. The Reynolds number is proportional to inertial force divided by viscous force.
The flow is
- laminar when Re < 2300
- transient when 2300 < Re < 4000
- turbulent when 4000 < Re
The study of fluids - liquids and gases. Involving velocity, pressure, density and temperature as functions of space and time.
The Darcy-Weisbach equation can be used to calculate the major pressure and head loss due to friction in ducts, pipes or tubes.
The entrance length is the length in a tube or duct after an obstruction - until the flow velocity profile is fully developed.
Kinematic viscosities of some common liquids like motor oil, diesel fuel, peanut oil and many more.
Typical fluid flow velocities for common liquids, gases and vapors.
Static pressure graphical presentation throughout a fluid flow system.
Introduction and definition of the dimensionless Reynolds Number - online calculators.
Friction loss in steel pipes for fluids with viscosities ranging 32 - 80000 SSU.
Absolute viscosity for water in centipoises for temperatures between 32 - 200oF.
Reynolds number for clean cold water flow.