CAJ | 학술논문

利用FLUENT软件数值计算了二维柔性鳍作升沉纵摇运动时的推力系数及推进效率,探讨了修正Bose变形方程、均匀载荷和非均匀载荷悬臂梁变形方程等三种柔性模式下纵摇轴位置对摆动鳍推进性能的影响,其中纵摇轴在尾缘处能够获得更大的推力,而最高的推进效率分别对应修正Bose模式下纵摇轴距首缘1/3弦长处和悬臂梁柔性变形模型下纵摇轴距首缘2/3弦长处,同时计算分析了斯特劳哈尔数、最大攻角等参数对柔性鳍水动力性能的影响,建立了最大推力系数和最高推进效率所对应的参数区间,其中低St数的最高推进效率发生在低αmax,高St数的最高推进效率发生在高αmax.
이용FLUENT연건수치계산료이유유성기작승침종요운동시적추력계수급추진효솔,탐토료수정Bose변형방정、균균재하화비균균재하현비량변형방정등삼충유성모식하종요축위치대파동기추진성능적영향,기중종요축재미연처능구획득경대적추력,이최고적추진효솔분별대응수정Bose모식하종요축거수연1/3현장처화현비량유성변형모형하종요축거수연2/3현장처,동시계산분석료사특로합이수、최대공각등삼수대유성기수동력성능적영향,건립료최대추력계수화최고추진효솔소대응적삼수구간,기중저St수적최고추진효솔발생재저αmax,고St수적최고추진효솔발생재고αmax.
The thrust coefficients and propulsive efficiency of a two-dimensional flexible fin with heaving and pitching motion were computed using FLUENT. The effect of different locations of the pitching axis on propulsive performance was examined using three deflexion modes which are respectively, modified Bose mode, cantilever beam with uniformly distributed load and cantilever beam with non-uniformly distributed load. The results show that maximum thrust can be achieved with the pitching axis at the trailing edge, but the highest propulsive efficiency can be achieved with the pitching axis either 1/3 of the chord length from the leading edge in modified Bose mode, or 2/3 of the chord length from the leading edge in cantilever beam mode. At the same time, the effects of the Strouhal number and maximal attack angle on the hydrodynamics performance of the flexible fin were analyzed. Parameter interval of the maximum thrust coefficient and the highest propulsive efficiency were gained. If the Strouhal number is low, high propulsive efficiency can be achieved at low αmax, and vice versa.