开孔分布对空腔流动特性的分析

开孔分布是影响空腔流动的一个重要因素.为了对开孔空腔流动有更深的认识,采用大涡模拟(LES)的方法,以Suboff艇体母线建立二维模型,研究4种开孔分布对空腔流动阻力,频谱特性及内外流交换的影响.对计算结果的分析表明,由于艇体表面的压力分布不同,孔附近产生纵向压力差,促使空腔内外流动交换,增加主艇体首尾压差阻力,进而使得总阻力增大.计算结果表明艇体阻力增加与内外流交换的密切相关,开孔位于中部时总阻力增量最小,内外流增量最小,开孔均匀分布时引起内外流流动交换剧烈,阻力增量最大,而且开孔引起总阻力波动幅值增加,频率分布特性发生相应的改变,开孔使得大幅波动频带变宽,可以预测噪声强度增加,频带变宽.

Analysis of cavity flow characteristics by hole distribution

Cavity flow depends greatly on hole distribution.To make hole cavity flow more clear, a large eddysimula-tion (LES) method is used to establish a two-dimensional model of SUBOFF hull busbar to study the effect of four kinds of hole distribution on cavity flow resistance, spectral characteristics and internal and external flow exchange in this paper. The analysis of the results shows that, due to the different pressure distribution on the surface of the hull, the longitudinalpres-sure difference is generated in the vicinity of the hole, which promotes the exchange of the inside and the outside of thecav-ity and increases the head-end pressure difference resistance of the main body. The results show that the increase of hullres-istance is closely related to the exchange of internal and external flow. When the opening is in the middle, the totalresist-ance increase is the smallest, the increment of internal and external flow is the smallest, and the flow of the internal andex-ternal flow is intense and the resistance is the largest. The opening of the hole causes the total resistance fluctuationamp-litude to increase, the frequency distribution characteristic changes accordingly, the opening makes the large fluctuationfre-quency band widens, can predict the noise intensity increases, the frequency band widens.