小水线面双体船阻力及航态预报方法

Prediction method for resistance and hull gesture of a small waterplane area twin hull

为了在小水线面双体船船型设计阶段实现阻力与航态的快速预报,基于Dawson方法,通过船体局部网格快速划分迭代求解船体纵倾、升沉以及不同航态下的湿表面积变化,从而实现提高阻力预报精度和航行姿态的预报。同时针对不同数值处理对计算结果的影响进行了探讨。以排水式Wigley船型为例,将基于改进后Dawson方法的阻力与航态理论预报结果与试验结果、商业软件非线性方法的计算结果进行了对比,对所用理论及网格划分、表面积分等数值方法的选择进行了讨论与验证。运用验证后的理论及数值方法,对小水线面双体船型进行了兴波阻力、湿表面积、航行姿态及总阻力预报,并与试验结果进行对比,可以看出理论计算结果与试验结果在峰值与趋势上都吻合良好。研究表明,在小水线面双体船阻力预报时考虑航行姿态和湿表面积变化所产生的影响是十分必要的。验证了方法对于小水线面双体船阻力与航态的快速预报是可行有效的。

For fast prediction of resistance and hull gesture during the hull form design of a small waterplane ar- ea twin hull （SWATH） ship, based on Dawson＇ s method, the change of wetted surface area under different conditions, including trimming and sinkage, and hull gestures, was calculated by quick iterative re-mesh of ship sections. Thereby the predictions of resistance and hull gesture were improved. The effect of different nu- merical treatments on the results was discussed. With an example of the Wigley displacement hull, the theoreti- cal resistance and hull gesture, based on improved Dawson＇ s method, were compared with the experiment re- suits and a commercial nonlinear method. The theoretical method, mesh scheme, and surface integration were discussed and verified. By the validated theoretical and numerical methods, the wave making resistance, wet- ted surface area, hull gesture and total resistance of SWATH were predicted and compared with the experiment results. Both the peak value and tendency were in good agreement with the experiment results. It can be seen from the research that it is necessary to take the effects of hull gesture and wetted surface change into account when predicting the resistance of SWATH. This method is proven to be feasible and valid for predicting the re- sistance and hull gesture of SWATH.