Velocity Distribution in Turbulent Flow
In turbulent flow, the velocity of the fluid does not remain constant across the cross-section of a pipe or channel. Instead, it varies significantly due to the chaotic and swirling motions of the fluid particles.
- Near the Walls: The velocity of the fluid is lowest near the walls of the pipe or channel. This is due to the friction between the fluid and the walls, which slows down the fluid particles at the surface.
- Middle of the Flow: As you move away from the walls toward the center of the pipe or channel, the velocity of the fluid increases. This increase is most pronounced close to the walls, where the fluid accelerates rapidly away from the low-velocity boundary layer.
- Center of the Pipe: At the center of the pipe, the velocity reaches its maximum. This region is farthest from the walls and thus experiences less frictional effects. However, unlike in laminar flow where the velocity profile is sharply peaked at the center, the velocity profile in turbulent flow tends to be flatter at the top. This flatter profile is a result of the intense mixing and momentum exchange due to the turbulent eddies and fluctuations.
- Overall Shape of the Profile: The overall shape of the velocity profile in turbulent flow is more uniform across the cross-section compared to laminar flow. This is due to the high levels of turbulence which enhance mixing and tend to equalize the velocity differences across the flow.
Laminar and Turbulent Flow
Laminar flow and turbulent flow describe the movement patterns of fluids. Laminar flow is characterized by smooth, orderly layers of fluid sliding over one another without mixing, ideal for scenarios where minimal resistance is desired. Turbulent flow features chaotic, swirling patterns with irregular fluctuations, often causing increased energy dissipation and mixing.