The Reynolds number for the flow of a fluid, represented this way, is equal to the density 𝜌 of a fluid multiplied by that fluid speed times what’s called the characteristic dimension of the flow, we’ll call it capital 𝐿, all divided by the dynamic viscosity 𝜇 of the fluid. The Reynolds number of this flow is a number that indicates how laminar or turbulent the flow of water is. Let’s say that this is our pipe with water flowing through it.
What is the Reynolds number for the flow? The pipe has an internal diameter of 0.025 meters and the water flows at an average speed of 0.15 meters per second. Water flowing through a pipe has a dynamic viscosity of 8.9 times 10 to the negative four pascal seconds and a density of 1000 kilograms per cubic meter.
