This happens because the Reynolds number is a global estimator of the turbulence and does not characterize the flow locally. It occurs for a range of Reynolds numbers in which laminar and turbulent regimes cohabit in the same flow. The transition regime separates the laminar flow from the turbulent flow. Table 1: Reynolds number and different flow regimes Transition Regime Between Laminar and Turbulent Flows Problem Configurationįlow around a foil parallel to the main flowįlow around a cylinder whose axis is perpendicular to the main flow The following table shows the correspondence between the Reynolds number and the regime obtained in different problems. Different configurations of the same application may have different critical Reynolds numbers.
The Reynolds number is a property of the application. For this reason, it is important to understand the physics of the flow to determine the accurate domain of application and the characteristic length. The Reynolds number describes the global behavior of flow, not its local behavior in large domains, it is possible to have localized turbulent regions that do not extend to the whole domain. It is interesting to notice that the Reynolds number depends both on the material properties of the fluid and the geometrical properties of the application. It is the threshold between the laminar and the turbulent flow. The mean value of Reynolds number in the transition regime is usually named “Critical Reynolds number”. Beyond that range, the flow becomes fully turbulent. This regime is usually referred to as the “transition regime” and occurs for a specific range of the Reynolds number. When the Reynolds number exceeds a threshold value, semi-developed turbulence occurs in the flow. \(\nu\) is the kinematic viscosity of the fluidįluid Flows and Their Corresponding Reynolds Number ValuesĪt low values of Reynolds number, the flow is laminar. \(\mu\) is the dynamic viscosity of the fluid. \(d\) is the characteristic length (or hydraulic diameter). \(u\) is the macroscopic velocity of the fluid. The distinction between laminar and turbulent regimes was first studied and theorized by Osborne Reynolds in the second half of the 19th century. The Reynolds number is proportional to inertial force divided by viscous force.Join SimScale Today! Laminar Flow vs Turbulent Flow shear.) It indicates the relative significance of the viscous effect compared to the inertia effect. The Reynolds number is important in analyzing any type of flow when there is substantial velocity gradient (i.e. Turbulent or laminar flow is determined by the dimensionless Reynolds Number. 
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. Transitional flow is a mixture of laminar and turbulent flow, with turbulence in the center of the pipe, and laminar flow near the edges. Shear stress in a turbulent flow is a function of density - ρ. Turbulent flow happens in general at high flow rates and with larger pipes. In turbulent flow vortices, eddies and wakes make the flow unpredictable. Shear stress in a laminar flow depends almost only on viscosity - μ - and is independent of density - ρ.
#Laminar flow pipe series
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.
Laminar flow generally happens when dealing with small pipes and low flow velocities. There are in general three types of fluid flow in pipes
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