船体低阶湿模态计算方法对比研究

Contrast Study on Calculation Method for Lower Order Wet Mode of Ship Hull

以某豪华游轮船体为研究对象,针对船体梁的低阶湿模态特性,将虚质量法应用于船体低阶湿模态计算,并与基于Lewis经验公式的附加质量法进行了对比分析。结果显示两种方法前四阶船体湿模态相差均在4.5%以内,特别是船体首阶湿模态相差仅0.3%。但附加质量法计算附连水质量过程复杂,且高阶模态计算偏差大。虚质量法计算过程简单,计算结果准确可靠,并且可在一次计算中得到船体前几阶低阶湿模态。虚质量法适用于船体低阶湿模态计算,对工程实际问题有一定的参考价值。

Taking ship hull of Luxury Cruise as research object, in allusion to characteristic of ship hull girder＇s lower order wet mode, virtual mass method was presented to calculate lower-order wet mode of ship hull and it was compared with additional mass method, which is a traditional method For calculating added water mass of ship hull, virtual mass method is based on the fluid structure interaction analysis for source-sink distribution theories, and additional mass method is based on Lewis＇s empirical formulas for three dimensional potential theories. The contrast between the calculated result of two methods shows that the discrepancy of the four orders wet mode were within 40, especially for the discrepancy of the first order, it was within 0.3%. Difference of the two method results changes in a relatively steady range. Additional mass method has a complicated process while calculating added water mass of ship hull, and has large deviation for higher order wet mode. Virtual mass method is easy to carry out and has the accurate result; it only needs to calculate once to get all of lower order wet mode. The proposed calculation method suits for calculating lower order wet mode of ship hull and provides a reference value for practical engineering problems.