Module 7. Flow through orifices, mouthpieces, notches and weirs

Lesson 23

NUMERICALS ON ORIFICE, MOUTHPIECE, NOTCH AND WEIR

23.1 Numericals

1. Calculate the flow velocity of water at the opening of an orifice if the orifice is located 4 m below the water surface in a tank.

Solution

= 8.85 m/s

2. Calculate the coefficient of velocity C_v if the actual velocity of jet is 5.1 m/s. Orifice is located 2m below the water surface in a tank.

Solution

= 0.814

3. Determine discharge through a internal mouthpiece (running free) if  there are a y mouth piece is 0.09 m². The distance between the centre of mouthpiece and free water surface is 2.5 m.

Solution

Where 

a = area of mouthpiece

h = distance between the centre of mouthpiece and free water surface.

= 0.315 m³/s

4.  Determine discharge through a internal mouthpiece (running free) if the are a of mouthpiece is 0.15 m². The distance between the centre of mouthpiece and free water surface is 3.0 m.

Solution

= 0.813 m³/s

5.  Determine flow rate through a rectangular hutch if L = 0.20 m and H = 0.15 m. Take value of c_d = 0.645

Solution

= 0.022 m³/s

6.  Determine flow rate through a triangular hutch if  H = 0.20 m and . Take value of c_d = 0.85.

Solution

= 0.0207 m³/s

7.  Determine flow rate through a rectangular weir if L = 0.30 m and H = 0.25 m. Take value of c_d = 0.95

Solution

= 0.105 m³/s