Abstract:

The Phillips spectrum was widely applied in real-time rendering of the irregular ocean wave. The structure of the Phillips spectrum was analyzed, and the frequency spectrum and directional distribution function of the Phillips spectrum were calculated. The frequency spectrum was similar with the P-M spectrum, so the constant A of the Phillips spectrum was computed by reference to the P-M spectrum, and the spectral wind speed was clarified. In addition to the Phillips spectrum, other spectra were tried. The P-M spectrum and the directional distribution function of the cos(-2s) form were used to construct the PM-cos2s spectrum, and the JONSWAP spectrum and the direction distribution function of the Poisson form were applied for constructing the J-Po spectrum. The three spectra mentioned above were used for rendering ocean wave, and the rendering results were compared. The waves rendered by the Phillips spectrum or PM-cos2s spectrum reflected the wind speed effect, and the wave generated by the J-Po spectrum showed the wind speed effect along with the fetch length effect. The frame rate of the three spectra shared the same value. Because the wave produced by the J-Po spectrum reflected the wind speed and fetch length influence, and the generated wave distributed in (-π,π］ of the wind direction, the J-Po spectrum was more suitable for the maritime simulator.

Key words: ocean wave rendering, Phillips spectrum, directional distribution function, wind speed