Reynolds Number for Flow in Pipe or Duct. For a pipe or duct the characteristic length is the hydraulic diameter. L = d h . where . d h = hydraulic diameter (m, ft) The Reynolds Number for the flow in a duct or pipe can with the hydraulic diameter be expressed as. Re = ρ u d h / …

The Reynolds number indicates the relative significance of the viscous effect compared to the inertia effect and the number is proportional to the inertial force divided by the viscous force. The flow is. Reynolds Number for one liter of water at approximately 20oC (68oF) flowing through pipes of different dimensions:

The Reynolds number (Re) of a flowing fluid is calculated by multiplying the fluid velocity by the internal pipe diameter (to obtain the inertia force of the fluid) and then dividing the result by the kinematic viscosity (viscous force per unit length).

Reynolds numbers (Re) describe the relationship between a fluid's velocity, the internal pipe diameter and the fluid's Kinematic viscosity. Reynolds number = Fluid velocity x Internal pipe diameter / Kinematic viscosity. Note: Kinematic viscosity (not Dynamic viscosity) must be used to calculate Reynolds numbers.

The Reynolds number, based on studies of Osborn Reynolds, is a dimensionless number comprised of the physical characteristics of the flow. Equation 1 is used to calculate the Reynolds number (N R) for fluid flow. Eq. 1 N g = ρ v D / ( µ g c) Where: N g = Reynolds number (unitless) v = average velocity (ft/sec) D = diameter of pipe (ft) µ ...

The Reynolds number has wide applications, ranging from liquid flow in a pipe to the passage of air over an aircraft wing. It is used to predict the transition from laminar to turbulent flow and is used in the scaling of similar but different-sized flow situations, such as between an aircraft model in a wind tunnel and the full-size version.

The Reynolds ( Re ) number is a quantity which engineers use to estimate if a fluid flow is laminar or turbulent. This is important, because increased mixing and shearing occur in turbulent flow.

What is the Reynolds number? The Reynolds number represents the ratio of inertial forces to viscous forces and is a convenient parameter for predicting if a flow condition will be laminar or turbulent. It is defined as a characteristic length multiplied by a characteristic velocity and divided by the kinematic viscosity.

The Reynolds number for pipe flow is defined as Re = DVρ/μ, where D is the pipe diameter, V is the average flow velocity in the pipe, ρ is the density of the flowing fluid and μ is the dynamic viscosity of the flowing fluid.

For the fluid passing through a pipe with a circular cross-section, the Reynolds number can be expressed as, `R_{e}=\frac{\rho uD}{\mu }` or `\frac{uD}{\nu }` Where d is the diameter of fluid flow. In this article, we’re going to discuss: Significance of reynolds number in heat transfer: What is critical reynolds number?