Question

A fluid is in streamline flow across a horizontal pipe of variable area of cross section. For this which of the following statements is correct?

• A. The velocity is maximum at the narrowest part of the pipe and pressure is maximum at the widest part of the pipe.
• B. Velocity and pressure both are maximum at the narrowest part of the pipe.
• C. Velocity and pressure both are maximum at the widest part of the pipe.
• D. The velocity is minimum at the narrowest part of the pipe and the pressure is minimum at the widest part of the pipe.

Answer 1

Answer: (A)

According to equation of continuity, $Av =$ constant Therefore, velocity is maximum at the narrowest part and minimum at the widest part of the pipe' According to Bernoulli's theorem for a horizontal pipe
$p+1 / 2 \rho v^{2}=$ constant
Hence, when a fluid flow across a horizontal pipe of variable area of cross-section its velocity is maximum and pressure is minimum at the narrowest part and vice versa.