PE Exam Practice Problem #48: Water Resources | Bernoulli - Energy - Continuity - Concept

Welcome to SolvedIn6: Free practice problems for the Professional Engineering Exam! Each question is styled after those created by the NCEES, and is usually solved in under 6 minutes, which is the average time you will have to solve each question on the Professional Engineering Exam.
In this problem, we are asked to find the diameter of a pipe hidden behind a wall and decide if it is larger or smaller than the diameter of the pipe that we can see. This is a conceptual problem that requires understanding of Bernoulli’s Equation.
If we write out Bernoulli's Equation, we can simplify it pretty quickly and make some informed decisions using information from the problem statement.
Step 1: The pipe is flat so the elevation term disappears from both sides of the equation.
Step 2: We know that the fluid pressure is lower on the other side of the pipe that we can’t see.
Step 3: In order for Step 2 to be true while head is conserved, the velocity in the second section of pipe has to be greater than the velocity in the first section.
Step 4: For flow (Q) to be constant through the pipe while velocity is higher in the second section, then area (and diameter) will have to be lower in the second section.
If you would like more Water Resources practice problems, please check out the rest of the playlist which this video is part of.
Please note that newer versions of the reference manual may have been released since this video was recorded. The search terms are usually still correct, but the page numbers listed in the video will be different.