Fluid tutorial 3_ans dr.waleed. 01004444149

1. Tutorial (3) Dr.waleed, Mob. 0100 4444 149 Page (1)
Tutorial (3)
1- In Fig. fluid 1 is oil (𝑆𝐺 = 0.87) and fluid 2 is glycerin at 20°C (SG =1.26).
If 𝑃𝑎 = 98 𝑘𝑃𝑎, Determine the absolute pressure at point 𝐴.
Solution
𝑃 ( ) ( ) 𝑃
𝑃 𝑃 ( ) ( )
𝑆𝐺
𝑃 ( ) ( )
( 𝑃 )

2. Tutorial (3) Dr.waleed, Mob. 0100 4444 149 Page (2)
2- In Fig. all fluids are at 20°𝐶. Determine the pressure difference (𝑃𝑎)
between points 𝐴 and 𝐵.
Note: Take the specific weights to be
Benzene: 8640 𝑁/𝑚3
Mercury: 133100 N/𝑚3
Kerosene: 7885 N/𝑚3
Water: 9790 N/𝑚3
Air: 12 N/𝑚3
Solution
𝑃 ( ) ( ) ( ) ( ) ( ) 𝑃
𝑃 𝑃 ( ) ( ) ( ) ( ) ( )
𝑃 𝑃 ( ) ( ) ( ) ( ) ( )
𝑃 𝑃 ( ) ( ) ( )
( ) ( )
𝑃 𝑃 𝑘𝑃𝑎

3. Tutorial (3) Dr.waleed, Mob. 0100 4444 149 Page (3)
3- In Fig, pressure gage 𝐴 reads 1.5 𝑘𝑃𝑎 ( 𝑎 𝑒). The fluids are at 20°𝐶.
Determine the elevations 𝑧, in meters, of the liquid levels in the open
piezometer tubes 𝐵 and 𝐶.
Solution
Take the specific weights to be
Air: 12 N/𝑚3
Gasoline: 6670 𝑁/𝑚3
Glycerin: 12360 N/𝑚3
Let piezometer tube B be at distance (H) above glycerin gasoline interface.
Let piezometer tube C be at distance (Y) above glycerin gasoline interface.
From (A) to (B)
1500 + (12)x(2) + (6670)x(1.5–H) – (6670)x(ZB – H – 1) =0
ZB = 2.73 m
From (A) to (C)
1500 + (12)x(2) + (6670)x(1.5) + (12360)x(1-Y) – (12360)(Zc-Y) =0
ZC = 1.93 m

4. Tutorial (3) Dr.waleed, Mob. 0100 4444 149 Page (4)
4- An 8 𝑐𝑚-diameter piston compresses manometer oil into an inclined 7𝑚𝑚
diameter tube, as shown in Fig. When a weight W is added to the top of
the piston, the oil rises an additional distance of 10 𝑐𝑚 up the tube, as
shown. How large is the weight, in 𝑁?
Solution
The pressure due to piston alone will be Pp
So
Pp = oil (h1 sin15) (1)
After adding the weight (W) the manometer equation will be
Pp + (W/Ap) = oil (h1 +10)sin15 (2)
So by subtract (1) from (2)
W/ Ap = oil (10 sin15)

5. Tutorial (3) Dr.waleed, Mob. 0100 4444 149 Page (5)
W = oil (10 sin15) Ap
W = (0.827)(1000)(9.81) ( sin15) ( ) = 1.05 N