The head of water over a rectangular weir is 26 cm. The length of the crest of the weir end contraction suppressed is 1.25 m. Find the discharge using the Francis formula.

The head of water over a rectangular weir is 38 cm. The length of the crest of the weir end contraction suppressed is 1.3 m. Find the discharge using the Francis formula.

A

0.56 m3/s

B

0.75 m3/s

C

0.85 m3/s

D

0.69 m3/s

The head of water over a rectangular weir is 28 cm. The length of the crest of the weir end contraction suppressed is 1.27 m. Find the discharge using the Francis formula.

A

0.346 m3/s

B

0.556 m3/s

C

0.788 m3/s

D

0.225 m3/s

Two centrifugal pumps P and R are available for use in a pipe flow system and their head-discharge characteristics are as follows. Pump P Pump R Discharge (cumecs) Head (m) Discharge (cumecs) Head (m) 0 40 0 45 0.12 35 0.14 40 0.2 28 0.24 35 0.3 18 0.3 28 The following statements (S1, S2, and S3) pertain to the head and discharge values during actual operation. Neglect losses in the system. Which of the following statements are correct? S1: When the two pumps P and R are connected in parallel, the discharge is 0.36 cumecs corresponding to a head of 35 m. S2: When the two pumps P and R are connected in parallel, the discharge is 0.36 cumecs corresponding to a head of 70 m. S3: When the two pumps P and R are connected in series, the discharge is 0.3 cumecs corresponding to a head of 46 m.

A

S2 only

B

S1 and S3

C

S1 and S2

D

S2 and S3

The discharge over a rectangular weir, considering the velocity of approach, is (where H₁ = H + H_a)
(H₁ = Total height of water above the weir, H = Height of water over the crest of the weir and H_a = Height of water due to velocity of approach)

A

$$\frac{2}{3}{{\text{C}}_{\text{d}}} \times {\text{L}}\sqrt {2{\text{g}}} \left$$

B

$$\frac{2}{3}{{\text{C}}_{\text{d}}} \times {\text{L}}\sqrt {2{\text{g}}} \left$$

C

$$\frac{2}{3}{{\text{C}}_{\text{d}}} \times {\text{L}}\sqrt {2{\text{g}}} \left$$

D

$$\frac{2}{3}{{\text{C}}_{\text{d}}} \times {\text{L}}\sqrt {2{\text{g}}} \left$$

A weir is said to be narrow-crested weir, if the width of the crest of the weir is __________ half the height of water above the weir crest.

A

Equal to

B

Less than

C

More than

D

None of these

A weir is said to be broad crested weir, if the width of the crest of the weir is ________ half the height of water above the weir crest.

A

Equal to

B

Less than

C

More than

D

None of these

Statement (I): The ogee spillway is a control weir having an S-shaped crest profile which provides a high discharge coefficient without causing cavitations. Statement (II): The crest profile of ogee spillway conforms to the lower nappe of flow over a ventilated sharp-crested weir and ensures a constant discharge coefficient for all heads.

A

Both Statement (I) and Statement (II) are individually true and Statement (II) is the correct explanation of Statement (I)

B

Both Statement (I) and Statement (II) are individually true but Statement (II) is not the correct explanation of Statement (I)

C

Statement (I) is true but Statement (II) is false

D

Statement (I) is false but Statement (II) is true (II) is true:

A weir is said to be narrow-crested, if the width of the crest of the weir is Where H = height of water above weir crest

A

equal to H

B

more than H

C

less than H

D

None of the above

For discharge over ogee weir discharge is directly proportional to length but for discharge over narrow crested weir it is inversely proportional to length.

A

True

B

False

The discharge passing over an ogee spillway is given by (where, L is effective length of spillway crest and H is the total head over the spillway crest including velocity head.)

A

$${\text{CL}}{{\text{H}}^{\frac{3}{2}}}$$

B

$${\text{CH}}{{\text{L}}^{\frac{3}{2}}}$$

C

$${\text{CL}}{{\text{H}}^{\frac{5}{2}}}$$

D

$${\text{CL}}{{\text{H}}^{\frac{1}{2}}}$$

The head of water over a rectangular weir is 26 cm. The length of the crest of the weir end contraction suppressed is 1.25 m. Find the discharge using the Francis formula.

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