UCF Geology Science Worksheet

NAME:_________________________________________________Environmental Hydrology
Homework: #5 Open Channel Flows and Manning
Points: 120
Turn in: Scan or photograph and submit via Canvas. Do NOT turn in a paper copy unless
absolutely necessary.
Question 1 (30 points): Write out the conservation of energy (CoE) for the following
system. Additionally, on the image below, identify and label all components of head and
draw and label the HGL and EGL.
Question 2 (30 points): Recall the Reynolds Number (Re) is the ratio of inertial to viscous
forces acting on a body of water. It allows us to determine if an open channel flow system,
groundwater system, or pipe is turbulent and if certain equations and conditions apply.
The calculation of Re is below along with representative units for each of the variables.
Show that the Reynolds Number is dimensionless.
𝑅𝑒 =
Units:
𝑘𝑔
𝜌 = 𝑑𝑒𝑛𝑠𝑖𝑡𝑦 ( 3 )
𝑚
𝑓𝑡
𝑣 = 𝑣𝑒𝑙𝑜𝑐𝑖𝑡𝑦 ( )
𝑠
𝐿 = 𝐿𝑒𝑛𝑔𝑡ℎ 𝑠𝑐𝑎𝑙𝑒 𝑜𝑟 𝑑𝑖𝑚𝑒𝑛𝑠𝑖𝑜𝑛 (𝑚)
𝜇 = 𝑣𝑖𝑠𝑐𝑜𝑠𝑖𝑡𝑦 (𝑑𝑦𝑛𝑎𝑚𝑖𝑐) =
𝑁
𝑠
𝑚2
𝜌𝑣𝐿
𝜇
Question 3 (30 points): A rectangular channel has a discharge of 25.6 cfs, a channel
bottom slope (S) of 0.001, and roughness of 0.032. If the cross-sectional wetted area is
13.21 ft2, what is the wetted perimeter? What is the flow depth given a bottom width of 4
feet?
Question 4 (30 points): A triangular channel has a flow depth of 8 m and a channel
bottom slope (S) of 0.001. The Manning n is 0.02. Channel height at the bank above the
bottom of the channel is 12 m. The angle of the side rises 10 degrees above horizontal.
What is the discharge?