中文摘要：

为了研究开缝宽度对中缝式V形钝体性能的影响，采用大涡模拟（LES）方法研究不同开缝宽度V形钝体尾流场．首先，模拟标准钝体流场，通过与文献数值模拟结果及实验结果比较，验证方法的正确性．然后，保持钝体张角为60。，阻塞比为0．33不变，分别研究缝宽比为0．1、0．2、0．3及0．4开缝钝体性能．大涡模拟得到的尾流场与文献观察到的实验现象一致．钝体回流区随缝宽比增加先增加后减小；阻力损失随缝宽比增加而减小，并均小于标准钝体．数值模拟表明，中缝流对流场的影响仅局限于钝体尾部一定区域内．过大的开缝宽度将使钝体性能极具恶化．综合比较，缝宽比为0．2时钝体回流区最大，比标准钝体增长24．3％，总压损失系数降低49．6％．

英文摘要：

In order to investigate the performance of the centrically slit bluff body, large-eddy simulation （LES） has been applied to analyze the wake flow of bluff bodies with different gap ratio. Firstly, the turbulent flow over the standard bluff body was simulated and the results agreed well with experimental data and published results, which means that the present method is capable for this research. Secondly, the cases with gap ratio 0.1, 0.2, 0.3 and 0.4 and the same open angle 60~ and blockage ratio 0.33 were studied. The predicted flow fields were equivalent to those observed with experiments. As the gap ratio increasing, the length of the reeireulation zone increases first and then decreases ; the total pressure coefficient decreases and is always smaller than that of the standard one. The influence induced by the gap flow vanishes after a distance from the bluff body. When the gap ratio becomes too large, the performance of the bluff body deteriorates. The slit bluff body with gap ratio 0.2 possesses the biggest re- circulation length of an increase by 24.3% and its total pressure loss coefficient decreases by 49.6% compared to the standard one.