雙體船船模阻力試驗技術確立與截流阻效應

ESTABLISHMENT OF RESISTANCE TEST TECHNIQUE AND INTERCEPTOR EFFECT FOR CATAMARAN MODEL

本研究使用一艘雙體船船模，裝設兩顆同型的力計（force gage）於雙體船兩個船體之推進軸系上，在國立成功大 學拖航水槽進行不同吃水與速度下之阻力量測。除了阻力試驗之外，運用 3D 掃描技術掌握雙體船船模的船型外型 後，並以 OpenFOAM 數值模擬船模在水槽試驗相同條件下，在滿載吃水與不同速度下之阻力，檢討數值模擬與水槽 船模阻力試驗的差異。 此雙體船的艉部配置有截流阻（interceptor），為了解截流阻在船體方艉 （transom stern）向下伸出深度大小對於阻力 的影響，進行一系列的阻力試驗；在試驗過程中，除了量測阻力數值之外，也同時量測前後吃水，掌握俯仰（trim）與 下沉（sinkage），瞭解截流阻造成船體姿態的變化狀況。 由試驗數據分析得到以下結果：成大水槽與國外水槽的阻力比對，最大相差約 8.9 N （5.65%）的船模總阻力，而 以 OpenFOAM 數值模擬的結果，得到的總阻力比水槽試驗的量測值大了約 27.46 N （15%）的船模總阻力。截流阻效 益的部分，效益最佳為下伸深度 8 mm，能減少 27.65 N （10.7%）的船模阻力，也能減少 9.2 mm 的下沉量與 0.4的俯 仰角度。

This study used a catamaran model to doing a resistance test in National Cheng Kung University towing tank, and installed two force gages on the thrust shafts of the two hulls in Catamaran model, and compared the results with other towing tank, to prove the method about test accuracy. In addition to the resistance test, the 3D scanning technology was used to grasp the ship shape of the catamaran model, and used OpenFOAM numerical simulation of the ship model, under the same conditions of the experiment test in different speeds and full load draught, to check the difference between the numerical simulation and model resistance test. The catamaran was equipped with an interceptor on transom stern, in order to understand the effect about that, a series of resistance tests were carried out; during the test not only measures resistance but also measures trim and sinkage, and understand the change of the ship attitude by the result. The experimental results show that: the resistance ratio between NCKU towing tank and foreign towing tank, the different of resistance was about 8.9 N (5.65%), and the results of the OpenFOAM numerical simulation show that the different of experiment resistance was about 27.46 N (15%). Finally, the best condition for the interceptor depth is 8 mm, which can reduce the model resistance about 27.65 N (10.7%), and also reduce the sinking amount of 9.2 mm and the pitch angle of 0.4 degrees.