Froude Number Calculator
Froude number and sub/supercritical classification for open-channel flow.
Supercritical flow can't 'feel' downstream conditions — transitions back to subcritical happen through a hydraulic jump that dissipates energy violently.
Formula
Froude Number Calculator is a free froude number for process, mechanical and water engineers — instant, accurate and 100% client-side, with the governing formula and reference shown next to the result so the number can be defended, not just quoted.
About Froude Number Calculator
Froude number and sub/supercritical classification for open-channel flow. The calculation implements Fr = V / √(g·y) (Chow, Open-Channel Hydraulics, ch. 3). Supercritical flow can't 'feel' downstream conditions — transitions back to subcritical happen through a hydraulic jump that dissipates energy violently.
How to use Froude Number Calculator
- 1Enter Flow velocity in m/s.
- 2Enter Hydraulic depth in m.
- 3Read Froude number instantly — no submit button needed.
- 4Need US units? Flip the SI/Imperial toggle and every field converts.
Why use Froude Number Calculator?
- ✓Implements the standard formula — Fr = V / √(g·y)
- ✓Reference cited on-page: Chow, Open-Channel Hydraulics, ch. 3
- ✓One-click SI ⇄ Imperial toggle — values convert in place, physics stays in SI
- ✓Live worked example: the substitution recomputes from your numbers
- ✓Built-in engineering verdict flags out-of-range results instantly
- ✓Runs entirely in your browser — nothing uploaded, free forever
Frequently asked questions
What formula does the Froude Number Calculator use?+
It computes Fr = V / √(g·y), per Chow, Open-Channel Hydraulics, ch. 3. The formula is displayed under the result along with a worked example substituted with your own inputs.
What should I keep in mind when using this calculator?+
Supercritical flow can't 'feel' downstream conditions — transitions back to subcritical happen through a hydraulic jump that dissipates energy violently.
Does this work for any fluid?+
Yes — density and viscosity are inputs (with common fluids suggested in the field hints), so the same physics applies to water, oils, gases and process fluids. Compute always runs in SI internally, so unit mix-ups can't corrupt the result.
Is the Froude Number Calculator free to use?+
Yes — completely free, no sign-up, no limits. It runs client-side in your browser, so inputs stay private and results are instant even on slow connections.
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