Question

Which one of the following phenomena in a pipe flow is termed as water hammer?

• A. The sudden rise of pressure in a long pipe due to sudden closure of valve.
• B. The rise of a pressure in a pipe flow due to gradual closure of valve.
• C. The rise of negative pressure.
• D. The zero pressure in a pipe flow.

Answer 1

The correct option is A The sudden rise of pressure in a long pipe due to sudden closure of valve.

Water hammer is a pressure surge or wave caused when water in motion is forced to stop or change direction suddenly (sudden momentum change). A water hammer commonly occurs when a valve closes suddenly at an end of a pipeline system, and there is sudden rise in the pressure. As a result a high pressure wave propagates in the pipe. It is also called hydraulic shock.