What is fluids in motion

The equation of continuity applies to any incompressible fluid. Since the fluid cannot be compressed, the amount of fluid which flows into a surface must equal the amount flowing out of the surface. The water flows through the hose and when it reaches the narrower nozzle, the velocity of the water increases. Speed increases when cross-sectional area decreases, and speed decreases when cross-sectional area increases.

This is a consequence of the continuity equation. If the flow Q is held constant, when the area A decreases, the velocity v must increase proportionally. For example, if the nozzle of the hose is half the area of the hose, the velocity must double to maintain the continuous flow. Continuity The equation of continuity works under the assumption that the flow in will equal the flow out.

Key Points Flow rate can be expressed in either terms of cross sectional area and velocity, or volume and time. Because liquids are incompressible, the rate of flow into an area must equal the rate of flow out of an area. This is known as the equation of continuity. The equation of continuity can show how much the speed of a liquid increases if it is forced to flow through a smaller area. For example, if the area of a pipe is halved, the velocity of the fluid will double.

Privacy Policy. Skip to main content. Search for:. Fluids in Motion. Flow Rate and the Equation of Continuity The flow rate of a liquid is how much liquid passes through an area in a given time. Learning Objectives Determine the flow rate based on velocity and area or elapsed time and justify the use of continuity in expressing properties of a fluid and its motion. Key Takeaways Key Points Flow rate can be expressed in either terms of cross sectional area and velocity, or volume and time.

Because liquids are incompressible, the rate of flow into an area must equal the rate of flow out of an area. This is known as the equation of continuity. The equation of continuity can show how much the speed of a liquid increases if it is forced to flow through a smaller area.

For example, if the area of a pipe is halved, the velocity of the fluid will double. Although gases often behave as fluids, they are not incompressible the way liquids are and so the continuity equation does not apply. Key Terms incompressible : Unable to be compressed or condensed. Licenses and Attributions.