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采用试验手段和计算流体力学方法(Computational Fluid Dynamics,CFD),研究基础抽吸率对汽车风洞试验的影响.首先,基于HD-2汽车风洞,运用试验方法完成对汽车风洞地面边界层厚度的测量,并对边界层的厚度进行评价,结果表明边界层的厚度与来流速度成反比;其次,综合运用数值模拟和试验测量方法,研究基础抽吸率大小对汽车风洞地面边界层厚度影响,研究发现随着抽吸率的变大,边界层厚度逐渐减小.最后,以MIRA汽车标模为对象,研究基础抽吸率对汽车气动特性的影响,当基础抽吸率小于0.06时,汽车的气动阻力系数随着基础抽吸率的增大而增大,进一步增大基础抽吸率,气动阻力系数不再产生明显变化;本文研究结果对汽车风洞抽吸系统的设计和最佳抽吸率的选取有重要的指导意义.
The influence of the basic suction rate on the wind tunnel test was studied by means of experimental methods and computational fluid dynamics (CFD) method.Firstly, based on the HD-2 wind tunnel, The thickness of the boundary layer is evaluated. The results show that the thickness of the boundary layer is inversely proportional to the velocity of the incoming flow. Secondly, the numerical simulation and experimental measurement methods are used to study the effect of the basic suction rate on the wind tunnel surface boundary layer The thickness of boundary layer gradually decreases with the increase of suction rate.Finally, the influence of basic suction rate on aerodynamic characteristics of automobile is studied with MIRA automobile model. When the basic suction rate is less than 0.06 , The aerodynamic drag coefficient of the vehicle increases with the increase of the basic suction rate and further increases the basic suction rate, and the aerodynamic drag coefficient no longer changes obviously. The results of this paper are helpful for the design of the wind tunnel suction system The best suction rate of choice has important guiding significance.