The other parameters, such as Xvv’ and Xrr’, are various non-linear coefficients obtained from captive model tests and applied when a ship is berthing, short turning or crabbing. In this study, the average added resistances, wave-induced steady lateral forces, and yaw selleck screening library moments to the ship by wind-wave and swell are combined, and a ship headed in a straight direction for about 1 h, and the hydrodynamic

and external forces were simplified. Only the advance, drift, and rotation motions in smooth water are considered. The simulation periods were from September 2, 00:00 UTC, to September 8, 00:00 UTC, 2004 (No. 1) and October 3, 00:00 UTC, to October 9, 00:00 UTC, 2009 (No. 2). Fig. 2 shows the weather charts when these two typhoons were closest to Osaka Bay. In the case of No. 1, the typhoon passed on the north side of Osaka Bay. In the case of No. 2, the typhoon passed on the south side. As shown in Fig. 3, three areas for nesting were calculated in each case to simulate winds more accurately. In both cases, the vertical grid is 28 from top pressure to ground pressure. Detailed information calculated by WRF is shown in Table 1. As shown in the Fig. 4 and Fig. 5, a strong south wind blew when the NO. 1 typhoon was closest to Osaka Bay, while a strong north wind blew in the case

of NO. 2 typhoon. The calculated wind velocity and direction were compared with the observation data from JMA (Japan Meteorological Agency). They are mostly consistent when these two typhoons were closest to Osaka BMS-387032 mw Bay, which was also the time period the simulation was conducted. Complicated very topography, such as the mountains located around Osaka Bay and the artificial islands along the coastline, may contribute to the difference. The wind calculated from WRF was applied into the tidal simulation of POM. The grid divisions in the x and y directions are the regular mesh, while the sigma coordinate system is used in the vertical direction. In these two typhoon cases, the grid number

is 528×901 (NO. 1 typhoon) and 648×855 (NO. 2 typhoon) in the x–y axis. The horizontal grid interval of Δx and Δy is 350 m in d03 in both cases. The calculation time interval is 2 seconds for both cases. The velocity distributions of the surface tidal current in Osaka Bay when these two typhoons were closest are shown in Fig. 6. The sea level height between observation and POM calculation was compared in Fig. 7. The change of surface current distribution, which is the main factor affecting ship navigation, was dramatic. The obvious influence of a typhoon on the tidal current can be found at the same time period. The numerical simulation of waves was carried out using the SWAN model. The water depth of the regular grid interval of Δx and Δy is 50 m. The mesh size is about 0.8 km, and the calculated time step is 10 seconds. The number of frequencies is 30, and the number of meshes in θ is given 36. As shown in Fig.