1. What is a Garden Hose Flow Rate Calculator?

Definition: This calculator estimates the volumetric flow rate through a garden hose using the Hagen-Poiseuille equation.

Purpose: It helps gardeners, irrigation planners, and DIY enthusiasts determine water flow for efficient watering systems.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Q \) — Flow rate (m³/s)
• \( r \) — Hose inner radius (m)
• \( \Delta P \) — Pressure difference (Pa)
• \( \mu \) — Water viscosity (Pa·s)
• \( L \) — Hose length (m)

Explanation: Flow rate increases with larger radius (strongly, to the 4th power) and higher pressure, but decreases with longer hoses and more viscous fluids.

3. Importance of Flow Rate Calculation

Details: Proper flow rate estimation ensures adequate water delivery, efficient irrigation, and proper system design.

4. Using the Calculator

Tips: Enter the hose radius (half of inner diameter), pressure difference (typically 100,000-300,000 Pa for household systems), water viscosity (default 0.001 Pa·s for water at 20°C), and hose length. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: Why does radius have such a big effect?
A: Flow rate depends on radius to the 4th power - doubling the radius increases flow 16 times!

Q2: What's a typical garden hose radius?
A: Standard hoses have about 0.0095m (3/8") to 0.0127m (1/2") inner radius.

Q3: How do I estimate pressure difference?
A: Household water pressure is typically 200,000-300,000 Pa (30-45 psi).

Q4: Does this work for any fluid?
A: Yes, but you must use the correct viscosity value for your fluid.

Q5: Why is my actual flow lower than calculated?
A: Real hoses have bends, connections, and roughness that reduce flow - this calculates ideal laminar flow.