A Novel Approach to Calibrating Wavemakers and Generating Wavemaker Transfer Functions

Limitations in our current knowledge of a ship in extreme wave conditions have been illuminated by the work being done by the US Navy on advanced hull-forms. Stochastic approaches to these phenomena are insufficient, and deterministic testing of these events must be performed if the physics is to be understood. Although modern computer controlled wavemakers provide the ability to generate regular sine waves, long crested multi-spectral waves, mixed seas of almost any sea spectra, and even “freak” waves, all of these systems require the wavemakers be tuned to the specific facility and that transfer functions between wavemaker settings and the generated wave be calculated. This tuning is performed to compensate for the facilities geometry, wave absorbers (beaches), etc, as well as to aid the researcher in using the wavemaker system. The Maneuvering and Seakeeping (MASK) basin at the Naval Surface Warfare Center, Carderock Division (NSWCCD) is a large rectangular basin, measuring 240 feet (73.2 m.) by 360 feet (109.7 m.). Two adjacent walls of the MASK are equipped with pneumatic wavemakers, while the other two banks are equipped with wave absorbing beaches. This paper describes the development of a feed-forward neural network model of the MASK wavemakers and demonstrates the utility of this approach in calibrating wavemakers and generating wavemaker transfer functions.