1. Fluid Mechanics II
Lecture 9
Muhammad Usman

2. Airfoil Theory
• Angle of inclination depends on the geometerical
position of the body with respect to motion.
• Flat plate inclined at 4 the ratio of lift to drag
force is about 6.
To increase this ratio
• The plate is given a slight curvature in its bottom
• By nicely rounding off the front end of the plate
• Providing sharpe edge in the end.

3. Reciprocating Pump
• L=Length of the stroke
• A= Cross sectional Area
• N= No. Of revolutions per mint.
• Discharge of Water= LAN/60.
• Discarge of water for double acting
pump.=2LAN/60.

4. Slip of Pump
• The difference between actual and
theoretical discharge is known as slip of
the pump.
• Force on the piston during suction
stroke=wHsA
• Force on the piston during delivery
stroke= wHdA
• Power= wQ(Hs+Hd)

5. Indicator Diagram

6. Variation of Pressure In section
and Delivery pipes due to
acceleration of the piston

7. Effect of Acceleration on the
Indicator Diagram

8. Example 1
• A single acting reciprocating pump has a
plunger of diameter 300mm and stroke of
200 mm. If the speed of the pump is 30
r.p.m. and its delivers 6.5 litres/sec of
water find the coefficient of discharge and
the percentage slip of the pump.

9. Example 2
• A single acting reciprocating pump, having
plunger diameter 125 mm and stroke
length 300 mm is drawing water from a
depth of 4 meters from the axis of the
cylinder at 24 r.p.m The length and
diameter of suction pipe is 9 meters and
75 mm respectively. Find the pressure
head on the piston at the begining and
end of the suction stroke, if the barometer
reads 10.3 m of water.