Entrainment

Definition

Entrainment is the process by which a fluid flow captures and carries along additional fluid from its surroundings. This phenomenon often occurs in turbulent flows and can significantly affect the behavior and properties of the fluid stream.

5 Must Know Facts For Your Next Test

1. Entrainment commonly occurs in turbulent flows, where mixing is enhanced due to chaotic eddies and vortices.
2. The rate of entrainment depends on factors such as the velocity of the primary fluid stream and the density difference between the fluids involved.
3. Entrainment can impact the efficiency of various engineering applications, including jet engines, pumps, and ventilation systems.
4. In Bernoulli's principle applications, entrainment affects pressure distribution along a streamline by altering the effective cross-sectional area through which fluid moves.
5. Mathematical models of entrainment often involve empirical correlations derived from experimental data to predict flow behavior.

Review Questions

• How does turbulent flow influence the rate of entrainment?
• What are some practical applications where entrainment plays a crucial role?
• How does entrainment affect pressure distribution in fluids governed by Bernoulli's principle?

Related terms

Turbulent Flow:

A type of fluid flow characterized by chaotic changes in pressure and flow velocity, leading to enhanced mixing and momentum transfer.

Bernoulli's Equation:

$$P + \frac{1}{2} \rho v^2 + \rho gh = \text{constant}$$; an equation representing conservation of energy for incompressible, non-viscous fluids in steady flow.

Pressure Gradient:

The rate at which pressure changes over a given distance within a fluid, often influencing flow direction and velocity.