25°Ahmed模型射流主动控制气动减阻策略

Strategy of Active Flow Control to Reduce Aerodynamic Drag with Steady Jet for 25°Ahmed Model

摘要:

采用剪切应力输送(SST) κω(湍动能比耗散率)湍流模型对标准25°Ahmed模型进行基于计算流体力学(CFD)数值模拟的稳态射流减阻研究.在模型尾部设置射流孔，分别探究各位置处射流孔的孔径、到边线的距离、形状、射流速度和角度的最佳值，分析不同射流状态对流场结构、总阻力系数及局部阻力系数的影响.仿真的基本工况与风洞实验数据一致性很好，验证所采用数值方法的准确性和可靠性.研究结果表明，与未设置射流孔的模型相比，设置射流方案的模型尾流结构得以改善，纵向涡得以抑制，同时其阻力系数明显降低.单独位置布置射流孔方案中在斜面上方进行射流时，阻力系数最低，为0.252 2，减阻率为11.3%.通过正交试验获得最佳组合方案得到阻力系数0.246 7，减阻率达13.23%.

Abstract:

Based on computational fluid dynamics(CFD) numerical simulation method, aerodynamic drag reduction of 25°Ahmed model with active flow control of steady jet are researched using shear stress transport(SST) κ-ω turbulent model. Jet holes are located at the model tail to study the optimum parameters of hole diameter, distance to the nearest side edge, shape, jet velocity and jet angle, and to analyze the influence of different jet state to the flow structure, total drag coefficient and local drag coefficient. In addition, the numerical simulation results are in good agreement with the date from wind tunnel experiment, which verifies the accuracy and reliability of present numerical method. The numerical results indicate that the wake structure with flow control is significantly improved and the longitudinal vortex is effectively suppressed, compared to the one without control. Simultaneously, the drag coefficient significantly decreases. In the scheme of placing jet hold on the single location, the one placing jet at the top of slant get the lowest drag coefficient 0.252 2 (with 11.3% drag reduction). The drag coefficient of the optimal combining scheme obtained by orthogonal experiment method is 0.246 7 (with 13.23% drag reduction).