Fluids Lecture

1
Lecture 7

• Recap lecture 6
• - Developed equation to describe pressure in the
  atmosphere

- Applied hydrostatics principles to problems
Problem Set 2, due on Friday, September 10th
2.10, 2.20, 2.24, 2.28, 2.36

• Focus of todays lecture
• - Verify problem solution you were expected to
  compete from last lecture
• - Examine hydrostatic forces on planar submerged
  surfaces with the goal
• of finding magnitude and line of action of net
  hydrostatic force

2
Lecture 7 - continued
To Express Pc in terms of mms of Hg

• Substitute numerical values

3
Lecture 7 - continued

• Read section 2.5, MYO, 3rd edition on
  absolute/gage pressure/textbook
• convention, concept of pressure head on page 46

• Manometry - Demo

Assumptions Static fluid, gravity is the only
body force, z axis vertical

• Read 2.6.3 and 2.7, MYO, 3rd edition for other
  pressure measuring devices

4
Lecture 7 - continued

• Hydrostatic forces on submerged surfaces

- Begin by considering forces on planar
surfaces - Basic ideas are the same when
considering curved surfaces

• Planar surface analysis

Goal

• To find magnitude of force on a planar surface
  submerged in a
• fluid
• To find location of net force or Center of
  Pressure

5
Lecture 7 - continued
Here yc is the y-coordinate of centroid of area
6
Lecture 7 - continued

• Introduce Module 2 briefly (Surface tension
  module) at the end of lecture

• At the beginning of lecture, point to website
  for course
• http//stripe.colorado.edu/mcen3021