Development of free running simulator using viscous CFD

采用移动网格技术，基于URaNS求解器SURF开发了机动模拟器。舵面采用局部网格变形处理，而整个计算域则移动以处理船舶运动。应用该程序求解了大阪埃索的曲折机动，并将计算结果与已有的海试数据进行了比较，计算结果定性地反映了右岸回转与左岸回转的差异趋势。10/10曲折机动的计算结果与海试数据基本吻合。当转向角变为20/20时，偏航角、转速角和漂移角的相位滞后明显。造成这种差异的两个可能原因是缺乏舵面积和舵/船尾附近的网格分辨率来捕捉船体和转向运动产生的涡流。

Maneuvering simulator is developed based on URaNS solver SURF with moving grid technique. The steering is treated by local grid morphing while the whole computational domain moves for the treatment of ship motions. The code is applied to solve turn zig-zag maneuvers for ESSO OSAKA, then the results are compared with the available sea trial data.The computational results of turning circle maneuver qualitatively capture the trend of difference between starboard side turning and port side turning. The computational results of 10/10 zig-zag maneuver generally agree well with the sea trial data. Once the steering angle becomes 20/20, the phase lag becomes apparent in yaw angle, rate of turn and drift angle. Two possible reasons for this discrepancy are the lack of rudder area and grid resolution in the rudder/stern vicinity to capture vortices originated from hull and steering motions.