Developed through a partnership between the University of Utah College of Engineering
and Granite School District
2.5 Fluid Mechanics
Summary
Students are introduced to Bernoulli’s Equation and use a simplified version to
perform hydrostatic pressure and flow rate calculations.
Learning Objectives
After this class, students will be able to:
• Calculate pressure as a function of water tower height.
• Calculate velocity and volumetric flow rate as a function of height.
• Identify differences between real flow and frictionless flow situations.
• Identify the two purposes of a water tower.
Materials
• Each student will need the Fluid Mechanics Exercises worksheet, a
pencil and a calculator.
Time
80 minutes
Procedure/Pacing
1. Ask class to give examples of how pressure changes with depth of a
fluid. (Swimming, ears popping when going up and down hill, etc.)
2. Most municipal water systems are supplied by water towers. Why do
communities use water towers?
a. Consistent source of water even during power or pump outages.
b. Need only size a pump to meet average demand, and not peak
demand.
3. Explain that students will be building and testing their own water
supply network in the next lab. First, it is necessary to get a feel for
what is happening within the network.
4. First we need to understand how depth in a fluid (or height of a water
tower) affects the pressure in a fluid.
Example Calculation of Pressure in a Fluid:
Calculate the pressure acting at 4 feet below the surface in a column of water.
Things to know before we begin:
ρ = fluid density = 1.94 slugs/ft3 for H2O at 32 °F.
1 slug = 1 lbf/(1 ft/s2), where lbf is pound-force, the
force unit in the British unit system
g = 32.17 ft/s2
4 ft
