Flow Rate in Cubic Feet per Second Calculator
Calculate and convert flow rates for hydraulic engineering and water management
Flow Rate Calculator
Flow Rate Results:
Cubic Feet per Second (CFS)
Gallons per Minute (GPM)
Cubic Meters per Second
Flow Rate Formula:
Where:
- Q = Flow Rate (cubic feet per second, CFS)
- A = Cross-Sectional Area (square feet, ft²)
- v = Flow Velocity (feet per second, ft/s)
Did you know?
A flow rate of 1 cubic foot per second (CFS) is equivalent to approximately 448.8 gallons per minute (GPM) or 0.02832 cubic meters per second.
Understanding Flow Rate in Cubic Feet per Second (CFS)
Flow rate is a measure of the volume of fluid passing a point in a system per unit of time. In hydraulic engineering and water management, cubic feet per second (CFS) is a common unit used to quantify flow rate, especially for rivers, channels, and large water systems.
Applications of Flow Rate Calculations
- River Management: Monitoring river flow rates for flood control and ecological health
- Water Supply Systems: Designing and managing municipal water distribution
- Irrigation: Planning agricultural water delivery systems
- Hydroelectric Power: Calculating potential energy generation
- Stormwater Management: Designing drainage systems and culverts
- Industrial Processes: Monitoring fluid movement in manufacturing
Factors Affecting Flow Rate
- Cross-Sectional Area: Larger areas allow more fluid to pass through
- Flow Velocity: Faster moving fluids increase flow rate
- Pipe/Channel Shape: Different shapes have different flow characteristics
- Surface Roughness: Smoother surfaces allow more efficient flow
- Fluid Viscosity: Thicker fluids flow more slowly
- Pressure Differential: Greater pressure differences increase flow rate
Flow Rate Unit Conversion
Converting between different flow rate units is essential in water management and engineering projects. The table below shows common conversion factors:
| From | To CFS | To GPM | To m³/s |
|---|---|---|---|
| 1 Cubic Foot per Second (CFS) | 1 | 448.8 | 0.02832 |
| 1 Gallon per Minute (GPM) | 0.002228 | 1 | 0.00006309 |
| 1 Cubic Meter per Second (m³/s) | 35.31 | 15,850 | 1 |
| 1 Liter per Second (L/s) | 0.03531 | 15.85 | 0.001 |
Manual Conversion Tool
Conversion Results:
Enter a value and click Convert to see results
Practical Examples of Flow Rate Calculations
Example 1: Water Flow in an Irrigation Canal
Problem: An irrigation canal has a rectangular cross-section with a width of 5 feet and a water depth of 2 feet. If the water is flowing at 3 feet per second, what is the flow rate in CFS and GPM?
Solution:
- Calculate the cross-sectional area: A = width × depth = 5 ft × 2 ft = 10 ft²
- Calculate the flow rate in CFS: Q = A × v = 10 ft² × 3 ft/s = 30 CFS
- Convert to GPM: 30 CFS × 448.8 GPM/CFS = 13,464 GPM
Example 2: Water Supply Pipeline
Problem: A water supply pipeline has a circular cross-section with a diameter of 3 feet. If the flow rate needed is 50 CFS, what must be the flow velocity in the pipe?
Solution:
- Calculate the cross-sectional area: A = π × (diameter/2)² = π × (3/2)² = π × 2.25 = 7.07 ft²
- Rearrange the flow rate formula to find velocity: v = Q ÷ A = 50 CFS ÷ 7.07 ft² = 7.07 ft/s
- The required flow velocity is 7.07 feet per second.
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