What are 2 main causes of turbulent flow?

Turbulence is a fluid flow in which layers mix together via eddies and swirls. It has two main causes. First, any obstruction or sharp corner, such as in a faucet, creates turbulence by imparting velocities perpendicular to the flow. Second, high speeds cause turbulence.

What makes a flow turbulent?

Turbulent flow is a type of fluid (gas or liquid) flow in which the fluid undergoes irregular fluctuations, or mixing, in contrast to laminar flow, in which the fluid moves in smooth paths or layers. In turbulent flow the speed of the fluid at a point is continuously undergoing changes in both magnitude and direction.

How can we stop turbulent flow?

Changing the Reynolds number; fluid properties, velocity, scale. Changing the geometry; shallow diverging walls, airfoils, flow straighteners, flow isolators. Eddy size reduction; vibration or dither for example could encourage small eddies to form instead of large eddies, airfoils, flow straighteners.

What conditions can create turbulence in a system?

The stronger the wind speed (generally, a surface wind of 20 knots or higher is required for significant turbulence), the rougher the terrain and the more unstable the air, the greater will be the turbulence. Of these factors that affect the formation of turbulence, stability is the most important.

What causes fluid to flow?

Fluid flow is often present during solidification and upsets the diffusion of solute and heat assumed above. Fluid flow during solidification can be caused by the density difference between liquid and solid (shrinkage flow), or by the action of gravity on density gradients within the fluid phase itself.

What factors decides the type of flow in pipes?

Fluid flow in pipes is affected by many different factors:

• The viscosity, density, and velocity of the fluid.
• Changes in the fluid temperature will change the viscosity & density of the fluid.
• The length, inner diameter, and in the case of turbulent flow, the internal roughness of the pipe.

What causes turbulent flow in blood vessels?

In arteries, turbulent blood flow can occur where atherosclerotic plaques narrow and vary the vessel lumen, where blood vessels branch or where aneurysms are encountered. The pronounced bend in the ascending aorta also creates turbulent flow.

Is turbulent flow unsteady?

Turbulent flow is characterized by unsteady eddying motions that are in constant motion with respect to each other. At any point in the flow, the eddies produce fluctuations in the flow velocity and pressure.

What causes pressure in fluid?

The pressure in a liquid is due to the weight of the column of water above. Since the particles in a liquid are tightly packed, this pressure acts in all directions. For example, the pressure acting on a dam at the bottom of a reservoir is greater than the pressure acting near the top.

What is a turbulent flow in a pipe?

Turbulent flow occurs when the Reynolds number exceeds 4000. Eddy currents are present within the flow and the ratio of the internal roughness of the pipe to the internal diameter of the pipe needs to be considered to be able to determine the friction factor. In large diameter pipes the overall effect of the eddy currents is less significant.

What is the cause of turbulence?

This is completely chaotic and due to same the fluid particles flow randomly. Because of the same, the fluid velocity is also chaotic. Thus unbounded gain in kinetic energy cause the turbulence. The additional kinetic energy gain in fluid particles is due to some external forces or domain of problem.

What is the velocity distribution for turbulent flow?

Velocity Distribution for Turbulent Flow in Smooth Pipes: Prandtl’s universal velocity distribution equation is valid in the central region of the pipe where the turbulent flow is fully developed. But in the regions close to the pipe wall the flow is not fully turbulent, and is more close to laminar flow.

What causes fluid to flow through a pipe?

Resistance to flow in a pipe. When a fluid flows through a pipe the internal roughness (e) of the pipe wall can create local eddy currents within the fluid adding a resistance to flow of the fluid. Pipes with smooth walls such as glass, copper, brass and polyethylene have only a small effect on the frictional resistance.