What is the Reynolds number?
Reynolds number (RE) is a dimensionless number related to the fluid mechanics. It is one of the most important attributes used to summarize the forces on fluid and on the basis of its value is determined by turbulence or lack of fluid turbulence. The designation is named for Osborne Reynolds, which at the end of the 19th and early 20th century conducted many pioneering studies in liquid mechanics. Variations in the quantity are determined on the x mood graph axes, one of the more useful graphs in liquid mechanics. In other words, the number describes how likely the flow of laminar or turbulent for a given set of physical conditions. Laminary or smooth flow indicates that everything in the fluid flow moves in the same direction and these internal flows do not affect each other. On the other side of the turbulent flow indicates that disturbances or faith are created in the main flow.
The most common example of laminar and turbulent tThe eye can be found at the sink. When the water is turned on for the first time and does not flow too fast, it is clear. Most of the inner flows of water do not interact with each other and move in the same direction; This is a laminar flow and indicates a low Reynolds number. As the amount and speed of water increases, it embodies. The inner flows begin to knock each other in a turbulent flow and introduce air into the water stream.
Another example of the concept is to imagine an object moving with liquid. The faster the object moves, the denser the liquid and the more the object moves, the more likely the flow of the liquid will be turbulent. The more viscous or sticky the liquid is, the greater the chance of a thick fluidishness will act against the turbulent flow.
Mathematically, the Reynolds number is defined as:
re = ρ * v * l / µ
Where re = reynolds number
ρ = fluid density (usually lb/ft
v = ryChvost (usually ft/s or m/s)
l = travel length (usually ft or m)
In a tube or channel l = hydraulic radius (usually ft or m)
µ = dynamic fluid viscosity (usually lb/(ft*s) or kg/(m*s) or pa*s)
From the equation, it is clear that the Reynolds number is in direct proportion to the length. They also differ in proportion to the length and density of fluids. The numbers ρ , v and l all contribute to inertia forces, while µ only contributes to viscous forces.
For Re 2 300 or less fluid flow is considered laminar. On the other hand, the turbulent tokun Re is greater than 4,000. The values for the Reynolds number between these two quantities indicate temporary flows that can show the properties of both types of flow.
Reynolds number is used in many different fluids applications. This is an essential part of the calculations of the friction factor factor in some equations in fluid mechanics such as the Darcy - Weisba equationch. Another common use of the number comes in modeling organisms of swimming water and this application has been made from the largest animals - such as blue whale - to very small animals, including microorganisms. It even has an application when modeling air flow around objects such as aircraft wings.