Open Channel Flow – Rectangular Cross Section

A year ago I created a spreadsheet that calculates the discharge, the velocity, the Reynolds number and the type of flow (laminar, transitional, turbulent) of an open channel with trapezoidal cross section. This time I developed a spreadsheet that calculates the same parameters but for an open channel with rectangular cross section. Again, the Manning’s equation is used for the calculations.

First, go to “Step 1” and fill the channel’s width and depth. Automatically, the sheet will calculate some necessary parameters, such as wetted perimeter, hydraulic radius and others. Then, go to “Step 2” and fill the values in the green cells. There are two useful tables that will help you filling the Manning’s parameter, as well as the dynamic viscosity of water. If you have successfully filled the input values, the sheet will calculate the desired flow values (discharge, velocity and type of flow).