1Fluid Mechanics – Lecture 4
Fluid mechanics(wb1225)
Lecture 4:control volume analysis
Momentum equation
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Conservation of momentum
1 2
3 4
5
1
2
3 [1]
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Conservation of momentum
momentum flux:
• pressure forces• forces due to viscous stresses• forces by solid bodies that protrude through surface
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Example 3.9
maximum momentum transfer when jet direction is reversed
small angle deflection; forceis normal to vane, and F ~ θ
[2]
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Example
[1]
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Hydraulic jump
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2004 Tsunami
[1]
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Hydraulic jump
[1]
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Example 3.11
1D inlet
streamline, no mass flux,no shear
2D outlet
streamline, V = 0shear forces
Boundary layer over a flat plate
[2]
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Example 3.11
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Example 3.12
[2]
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Example: Pelton wheel
[3]
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Summary• Chapter 3: 3.1-3.4
• Examples: 3.1-3.6
• Problems: 3.36, 3.50, 3.51, 3.73, 3.86
14Fluid Mechanics – Lecture 4
Source1. Multimedia Fluid Mechanics DVD-ROM, G. M. Homsy, University of California, Santa Barbara2. Frank M. White, Fluid Mechanics, McGraw-Hill Series in Mechanical Engineering3. Pelton Turbine, http://www.eumarine.com