What is the velocity of flow in an 8 inch force main with a metered flow of 400000 gpd?

To determine the velocity of flow in an 8-inch force main carrying a flow rate of 400,000 gallons per day (gpd), it's essential to apply the appropriate formula for flow velocity.

First, convert the flow rate from gallons per day to cubic feet per second. There are 7.48 gallons in a cubic foot and 86,400 seconds in a day. Using these conversions:

1. Convert gallons to cubic feet:
   400,000 gpd ÷ 7.48 ≈ 53,355.51 cubic feet per day.

2. Convert days to seconds:
   53,355.51 cubic feet per day ÷ 86,400 seconds per day ≈ 0.617 cubic feet per second (cfs).

Next, calculate the cross-sectional area of the 8-inch pipe. The diameter is converted to feet (8 inches = 0.667 feet). The radius would be half of that, which is 0.3335 feet. Applying the area formula for a circle (Area = πr²), we find:

Area = π × (0.3335)² ≈ 0.349 square feet.

Now, use the flow rate and