MyQuestionIcon

1

You visited us 1 times! Enjoying our articles? Unlock Full Access!

Pascal's Law

In a reach of...

Question

In a reach of open channel flow, with $q = 2 m^{2} / s$ , the depth of flow at section A is 1.5m and at section B, 1.6 m. The difference in specific energies at the two-section can be correspondingly taken as 0.09 m. The bed slope is 1 in 2000. The mean energy slope between the sections is given as 0.003. What is the length of reach AB?

A

54 m with B on the upstream

No worries! We‘ve got your back. Try BYJU‘S free classes today!

B

36 m with A on the upstream

No worries! We‘ve got your back. Try BYJU‘S free classes today!

C

36 m with B on the upstream

Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses

D

54 m with A on the upstream

No worries! We‘ve got your back. Try BYJU‘S free classes today!

Open in App

Solution

The correct option is C 36 m with B on the upstream
Critical depth,
$y_{c} = {(\frac{q^{2}}{g})}^{1 / 3} = {(\frac{2^{2}}{9.81})}^{1 / 3} = 0.74 m$

$A s y_{A} = 1.5 m a n d y_{B} = 1.6 m a r e m o r e t h a n y_{c} s o t h e f l o w i s s u b c r i t i c a l .$

$∴ E_{A} < E_{B}$

Length of reach AB assuming B on the upstream will be

$L_{A B} = \frac{E_{B} - E_{A}}{S_{0} - S_{1}} = \frac{0.09}{\frac{1}{2000} - 0.003} = - 36 m$
$S i n c e L_{A B} is negative so B is on the upstream .$

Suggest Corrections

thumbs-up

1

Similar questions

Q. A short reach of a 2 m wide rectangular open channel has its bed level rising in the direction of flow at a slope of 1 in 10000. It carries a discharge of

4 m^{3} / s

and its Manning's roughness coefficient is 0.01. The flow in this reach is gradually varying. At a certain section in this reach, the depth of flow was measured as 0.5 m. The rate of change of the water depth with distance,

\frac{d y}{d x}

, at this section is _________ .

(u s e g = 10 m / s^{2}

)

Q. A 1 m wide rectangular channel has a bed slope of 0.0016 and Manning's roughness coefficient is 0.04. Uniform flow takes place in the channel at a flow depth of 0.5 m. At a particular section, gradually varied flow (GVF) is observed and the flow depth is measured as 0.6 m. The GVF profile at that section is classified as

Q. A short reach of a 3 m wide rectangular open channel has its bed level falling in the direction of flow at a slope of 1 in 10000. It carries a discharge of 5 cumecs and its manning's roughness coefficient is 0.012. The flow in the reach is gradually varying. At a certain section in this reach, the depth of flow was measured as 0.6 m. The rate of change of water depth with distance (i.e.,

\frac{d y}{d x}

) at this section is

\times 10^{- 3}

T a k e g = 10 m s^{- 2}

Q. A 3 m wide rectangular channel carries a flow of

6 m^{3} / s

. The depth of flow at a section P is 0.5 m. A flat-topped hump is to be placed at the downstream of the section P. Assume negligible energy loss between section P and hump, and consider g as

9.81 m / s^{2}

. The maximum height of the hump (expressed in m) which will not change the depth of flow at section P is

Q. A very wide rectangular channel carries a discharge of 8

m^{3} / s

per m width. The channel has a bed slope of 0.004 and manning's roughness coefficient, n=0.015. At a certain section of the channel, the flow depth is 1 m.

What Gradually Varied Flow profile exists at this section?

View More

Join BYJU'S Learning Program

similar_icon

Related Videos

lock

Pascal's Law

PHYSICS

Watch in App

explore_more_icon

Explore more

Standard XII Physics

Join BYJU'S Learning Program

CrossIcon