Dimensionless speed ratio J = V_A / (n·D) - the horizontal axis of every propeller open-water chart.
Formula
$$ J = \frac{V_A}{n \cdot D} $$Symbol legend
| Symbol | Meaning | Unit | Source |
|---|---|---|---|
| $V_A$ | Advance velocity at propeller disk | m/s | V·(1−w) |
| $n$ | Shaft revolutions per second | rev/s | rpm/60 |
| $D$ | Propeller diameter | m | propeller drawing |
| $J$ | Advance ratio | - | result |
Sources
- SNAME PNA Vol II Ch.6.
- Carlton - Marine Propellers and Propulsion.