Increment of skin-friction coefficient from measured hull roughness (AHR) using the ITTC-78 Townsin formulation.
Formula
$$ \Delta C_F = \left[ 110 \cdot \left(\frac{AHR}{L}\right)^{1/3} - 0.64 \right] \cdot 10^{-3} $$
Symbol legend
| Symbol | Meaning | Unit | Source |
|---|---|---|---|
| $AHR$ | Average hull roughness | µm | gauge measurement |
| $L$ | Waterline length | m | particulars |
| $\Delta C_F$ | Skin-friction roughness increment | - | result |
Sources
- Townsin - Paint roughness.