# Lecture #7

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## Lecture #7

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##### Presentation Transcript

1. z y x 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 today’s 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 Fluid Mechanics: Mahalingam

2. l3 C F E A l2 G Water l1 B D => Lecture #7 - continued To Express Pc in terms of mm’s of Hg • Substitute numerical values Fluid Mechanics: Mahalingam

3. A B h2 h1 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 Fluid Mechanics: Mahalingam

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 Fluid Mechanics: Mahalingam

5. hc q F x x yR z dA yc y dF dy h y y Lecture #7 - continued Here yc is the y-coordinate of centroid of area Fluid Mechanics: Mahalingam

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 Fluid Mechanics: Mahalingam