Torsional vibration analysis
Propeller damping plays an important role in torsional vibration analysis.
In the Nauticus Torsional Vibration tool, five different methods of damping calculation are available:
- Archer approach: Consider the propeller damping as a consequence of the propeller’s torque characteristics. Derive the damping coefficient from the propeller law. Suitable for both fixed pitch propeller and controllable pitch propeller.
- Frahm approach: Similar to Archer approach but using Frahm number.
- Schwaneke approach: Use Schwaneke empirical formula to calculate the propeller damping. It is dependent on the propeller geometry.
- Dynamic magnifier approach: Use the dynamic magnifier/dynamic magnifier percent to simulate the propeller damping. It is often used for MAN propellers.
- Variable approach: The dynamic magnifier percentage changes as function of propeller rotational speed.