In a convergent flow, what happens to velocity and pressure?

In a convergent flow, what happens to velocity and pressure?

• A. Velocity increases and pressure decreases
• B. Velocity decreases and pressure increases
• C. Velocity increases and pressure increases
• D. Velocity constant and pressure constant

Answer: (A)

In convergent flow the passage narrows, so to carry the same amount of air per second, the velocity must increase. As the fluid speeds up along a streamline, its static pressure decreases due to Bernoulli’s principle for incompressible, steady, frictionless flow. Total pressure would stay constant if there were no losses, but the key relationship here is that velocity rises while static pressure falls. So the correct description is that velocity increases and pressure decreases.

In convergent flow the passage narrows, so to carry the same amount of air per second, the velocity must increase. As the fluid speeds up along a streamline, its static pressure decreases due to Bernoulli’s principle for incompressible, steady, frictionless flow. Total pressure would stay constant if there were no losses, but the key relationship here is that velocity rises while static pressure falls. So the correct description is that velocity increases and pressure decreases.