Calculator
Enter any two known values. The selected target will be calculated after submission.
Plotly Graph
This chart shows how head changes with velocity for the active gravity setting.
Example Data Table
| Case | Velocity (m/s) | Gravity (m/s²) | Head (m) |
|---|---|---|---|
| Case A | 8.00 | 9.81 | 3.26 |
| Case B | 12.00 | 9.81 | 7.34 |
| Case C | 18.00 | 9.81 | 16.51 |
| Case D | 25.00 | 9.81 | 31.86 |
| Case E | 30.00 | 9.81 | 45.87 |
Formula Used
Primary equation: h = v² / 2g
This relation links velocity head with flow velocity and gravitational acceleration.
Rearranged for velocity: v = √(2gh)
Rearranged for gravity: g = v² / 2h
Use consistent units before solving. This calculator converts selected units internally to maintain accurate results.
How to Use This Calculator
- Select the variable you want to solve.
- Enter the two known values in the input fields.
- Choose matching units for each value.
- Set your preferred decimal precision.
- Press Calculate Now to view the result.
- Review the chart, summary metrics, and example table.
- Download the result as CSV or PDF if needed.
FAQs
1. What does h = v² / 2g represent?
It represents velocity head. The value shows how much height corresponds to a moving fluid’s kinetic energy under gravity.
2. Can I solve for velocity instead of head?
Yes. Choose velocity in the solve field, then enter head and gravity. The calculator will apply the rearranged equation automatically.
3. Why are unit choices important?
Mixed units can create incorrect results. This page converts selected units internally, which helps maintain consistent calculations and clean output values.
4. Is this useful for fluid mechanics work?
Yes. It is commonly used in Bernoulli analysis, pipe flow work, pump studies, and general velocity head estimation.
5. What gravity value should I enter?
For Earth-based work, 9.81 m/s² is standard. Other values may be used for special engineering assumptions or nonstandard study examples.
6. Why does head rise quickly with velocity?
Because velocity is squared. Doubling velocity creates four times the velocity head when gravity remains unchanged.
7. What does the chart show?
The graph plots head against increasing velocity values using the current gravity setting. It helps you see the nonlinear growth clearly.
8. Can I export the results?
Yes. Use the result export buttons for CSV and PDF. The example table also has its own export options.