侧风条件下地面涡来源和气动特性的数值研究

Numerical study on source and aerodynamic characteristic of ground vortex under crosswind condition

为了研究侧风条件下地面涡的涡量源和地面涡的气动特性,选取缩比进气道并对侧风条件下的流场进行了数值模拟。结果表明:90°侧风条件下,尾涡和环境涡量都是地面涡的重要来源,即使不存在环境涡量,尾涡仍然可以单独形成地面涡,尾涡-地面涡流动模型能够很好地解释这一现象。地面涡涡量随来流速度的增加先增大后减小,临界速度比随离地间隙的增大而增大。离地间隙增大一倍,临界速度比增大65%,地面涡涡量峰值减小30%。受到地面涡本身以及流动分离的影响,进气道的总压损失随着来流速度比的减小而增大。

Numerical simulation of scaling intake duct was carried out for the purpose of exploring the source and aerodynamic characteristic of ground vortex under crosswind condition.Results showed that trailing vortex and ambient vortex were both the major contributions to the production of ground vortex under 90 degree crosswind condition.Even though there was no ambient vorticity,ground vortex could still be there under 90 degree crosswindcondition as illustrated by the trailing vortex-ground vortex model.Vorticity of ground vortex increased to the maximum and then decreased with the increase of approaching flow velocity while the critical velocity ratio increased with the increase of height-to-diameter ratio.While the height-to-diameter ratio was doubled,the critical velocity ratio increased by 65%and the peak vorticity of ground vortex decreased by 30%.Total pressure loss of the intake duct increased with the decrease of approaching flow velocity ratio due to either ground vortex or flow separation.