Search results
Results from the WOW.Com Content Network
The plume from an ordinary candle transitions from laminar to turbulent flow in this Schlieren photograph. In fluid dynamics, the process of a laminar flow becoming turbulent is known as laminar–turbulent transition. The main parameter characterizing transition is the Reynolds number.
With respect to laminar and turbulent flow regimes: laminar flow occurs at low Reynolds numbers, where viscous forces are dominant, and is characterized by smooth, constant fluid motion; turbulent flow occurs at high Reynolds numbers and is dominated by inertial forces, which tend to produce chaotic eddies, vortices and other flow instabilities ...
Laminar flow occurs at lower velocities, below a threshold at which the flow becomes turbulent. The threshold velocity is determined by a dimensionless parameter characterizing the flow called the Reynolds number , which also depends on the viscosity and density of the fluid and dimensions of the channel.
The transition from laminar to turbulent flow. Turbulence is flow characterized by recirculation, eddies, and apparent randomness. Flow in which turbulence is not exhibited is called laminar. The presence of eddies or recirculation alone does not necessarily indicate turbulent flow—these phenomena may be present in laminar flow as well.
With respect to laminar and turbulent flow regimes: laminar flow occurs at low Reynolds numbers, where viscous forces are dominant, and is characterized by smooth, constant fluid motion; turbulent flow occurs at high Reynolds numbers and is dominated by inertial forces, which tend to produce chaotic eddies, vortices and other flow instabilities.
Reynolds Experiment (1883). Osborne Reynolds standing beside his apparatus. In 1883, scientist Osborne Reynolds conducted a fluid dynamics experiment involving water and dye, where he adjusted the velocities of the fluids and observed the transition from laminar to turbulent flow, characterized by the formation of eddies and vortices. [5]
Usually, there is a transition from laminar to turbulent as the plume moves away from its source. This phenomenon can be clearly seen in the rising column of smoke from a cigarette. When high accuracy is required, computational fluid dynamics (CFD) can be employed to simulate plumes, but the results can be sensitive to the turbulence model chosen.
A bypass transition is a laminar–turbulent transition in a fluid flow over a surface. It occurs when a laminar boundary layer transitions to a turbulent one through some secondary instability mode, bypassing some of the pre-transitional events that typically occur in a natural laminar–turbulent transition. [a]