Part D. Compute the following quantities: (a) Velocity of flow at section 1. (b) Specific energy at section 1. (c) Specific energy at section 2. (d) Depth of flow at section 2. Draw it also on the figure. (e) Velocity of flow at section 2. (f) The specific force (SF) at sections 1 and 2. (g) The momentum function (M) at sections 1 and 2. (h) The force acting on the step. (i) The direction of the force acting on the step i.e. upstream or downstream. (j) The critical depth for the flow. State any assumptions used for your calculations.
A channel step, shown in the figure below, is in a 12 m wide channel with discharge, Q, of 46 m3/s. The flow depth at section 1 is 1.6 m and the step height is 0.4 m. The bed of the channel, upstream and downstream of the step, is horizontal and smooth.
Part A. Sketch on the figure the variation of the pressure with depth at sections 1 and 2, and on the verticalface of the step. Sections 1 and 2 are located far enough from the step for the velocity to be essentially horizontal and uniform.
Part B. Draw the control volume contained between sections 1 and 2 and show on the figure the forces acting on it. Show also your choice for the positive direction of distance and of force.
Part C. Write the momentum equation as applied to the control volume between sections 1 and 2, using the sign convention you have chosen. Show the forces and velocities used in the momentum equation.
Part D. Compute the following quantities:
(a) Velocity of flow at section 1.
(b) Specific energy at section 1.
(c) Specific energy at section 2.
(d) Depth of flow at section 2. Draw it also on the figure.
(e) Velocity of flow at section 2.
(f) The specific force (SF) at sections 1 and 2.
(g) The momentum function (M) at sections 1 and 2.
(h) The force acting on the step.
(i) The direction of the force acting on the step i.e. upstream or downstream.
(j) The critical depth for the flow.
State any assumptions used for your calculations.
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