HE Lecture 10
HE Lecture 10
HE Lecture 10
Ratnakar Swain
(M. Tech. & Ph.D., IIT KGP)
Asst. Professor
Department of Civil Engineering
NIT Rourkela
CONTINUES
Calculation of 𝒚𝒚𝒄𝒄 T
Rectangular section
𝑸𝑸𝟐𝟐 𝑨𝑨𝟑𝟑 𝒄𝒄 y
=
𝒈𝒈 𝑻𝑻𝒄𝒄
𝒎𝒎𝟐𝟐 𝒚𝒚𝟓𝟓𝒄𝒄 1 y
= 𝒚𝒚𝒄𝒄 +
𝟒𝟒𝟒𝟒𝒚𝒚𝟒𝟒𝒄𝒄 m
𝑨𝑨𝒄𝒄 = (B + my)y
𝒃𝒃 𝑨𝑨𝒄𝒄 = (B + 1.5 x 1.2)x 1.2 = (B + 1.8)x 1.2
𝑻𝑻𝒄𝒄 = (B + 2my)
𝑻𝑻𝒄𝒄 = (B + 2 x1.5 x 1.2) = B + 3.6
𝑸𝑸𝟐𝟐 𝑨𝑨𝟑𝟑𝒄𝒄
=
𝒈𝒈 𝑻𝑻𝒄𝒄
(𝑩𝑩 + 𝟏𝟏. 𝟖𝟖)𝟑𝟑 (𝟏𝟏. 𝟐𝟐)𝟑𝟑 𝟏𝟏𝟏𝟏𝟐𝟐
⇒ =
𝑩𝑩 + 𝟑𝟑. 𝟔𝟔 𝟗𝟗. 𝟖𝟖𝟖𝟖
𝑩𝑩 + 𝟏𝟏. 𝟖𝟖 𝟑𝟑
⇒ = 𝟏𝟏𝟏𝟏. 𝟐𝟐𝟐𝟐𝟐𝟐
𝑩𝑩 + 𝟑𝟑. 𝟔𝟔
By trial and error B = 2.535m
5
Dr. R. Swain, Asst. Prof., NIT RKL
TRANSITION IN CHANNEL
• Width Contraction
a.When flow subcritical
b.When flow is supercritical
To cause the flow, u/s depth 𝒚𝒚𝟏𝟏 will change, it will decreases to have a higher specific energy
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Dr. R. Swain, Asst. Prof., NIT RKL