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飞艇大攻角绕流作为一种典型的分离与漩涡流动,相关研究具有较高难度和十分重要的意义。该文基于数值模拟方法,研究了飞艇大攻角绕流条件下的气动特性,分析了湍流模型选择和湍流强度设置等关键因素对模拟结果的影响。气动力、压力系数、流场显示细节等结果表明:SST k??模型和Realizable k??均能较准确地模拟飞艇周边流体流动现象,计算得到的气动参数和实验结果吻合良好,而S-A模型和实验存在较大差异;同时发现湍流强度对飞艇气动力存在较大影响,升阻力系数在湍流强度I>0.5%时随之线性增长。进一步引入了等效雷诺数的概念,证明与原始雷诺数类似,等效雷诺数对气动力影响存在相应的敏感区间,在计算和实验中值得加以注意。
As a typical separation and swirling flow, airstrips at high angles of attack are of great difficulty and significance. Based on the numerical simulation method, the aerodynamic characteristics of the airship around a large angle of attack are studied. The effects of the key factors such as turbulence model selection and turbulence intensity setting on the simulation results are analyzed. The results of aerodynamic force, pressure coefficient and flow field show that the SST k model and Realizable k can all accurately simulate the fluid flow around the airship. The calculated aerodynamic parameters are in good agreement with the experimental results. However, the SA model It is found that the turbulence intensity has a great influence on the aerodynamic force of the airship, and the drag coefficient increases linearly with the turbulence intensity I> 0.5%. The concept of equivalent Reynolds number is further introduced. It proves that similar to the original Reynolds number, the equivalent Reynolds number has corresponding sensitive range to the aerodynamic force, which deserves our attention in the calculation and experiment.