121. For laminar flow in circular pipes, the Darcy's friction factor f is equal to
64/Rₑ where Rₑ is Reynolds number
122. Surge wave in a rectangular channel is an example of
unsteady flow,non-uniform flow
123. The best hydraulic channel cross-section is the one which has a minimum wetted perimeter
124. Which is the best hydraulic section of the following open channel cross-sections ? semi-circle
125. Hydraulic jump is a steady flow,non-uniform flow
126. The hydraulic jump always occurs from below critical depth to above critical
depth
127. In a gradually varied flow the slope of energy grade line, hydraulic grade line and bottom of channel are all different
128. The flow in channels is considered to be in transitional state if the Reynolds
number is between 500 and 2000
129. The Froude number is defined as
where v is the mean velocity of flow, g is acceleration due to gravity and D is
hydraulic depth
130. For shooting flow the Froude number is greater than one
131. For uniform flow in a channel the total energy line, hydraulic gradient line and bottom of channel arc all parallel
132. The Chezy's coefficient has the dimension L¹/² / 2T⁻¹
133. If T is the friction factor, then the Chezy's coefficient is proportional to
134.The relationship between Manning's coefficient n and Chezy's coefficient c is
given by
135.The depth of flow for maximum velocity in a circular channel section with diameter equal to 1.5 m is 1.215 m
136.For maximum discharge in a circular channel section, the ratio of the depth of
flow to that of diameter of the channel is 0.95
137.A triangular channel section is most economical when each of its sloping sides
is inclined to the vertical at an angle of 45°
138.For a trapezoidal channel section to be most economical, its hydraulic radius must be equal to y/2
139. The critical state of flow through a channel section may be defined as the
state of flow at which the discharge is maximum for a given specific force
140. The critical state of flow in a non rectangular channel is expressed by
