论文部分内容阅读
汽车尾部湍流场是汽车压差阻力的主要来源,在HD-2汽车模型风洞中,首先使用测力天平和测压系统,对横摆角工况下汽车模型的气动六分力和纵对称截面48个测点的表面压力进行了测量,然后利用PIV测量技术对模型在横摆角分别为0°、15°的尾部湍流场进行了测量,获得该模型尾流场的速度场、涡量场和雷诺应力流场信息,通过计算得出尾流场区域空间相关系数和湍流积分尺度。结果表明:在横摆角工况下,汽车模型尾部涡流的结构呈现向上发展的趋势;尾流场拖拽涡的范围和强度的增大导致了模型气动力出现较大的增加;湍流积分尺度的变化表明,尾部涡流区的分离噪声与涡流分离位置有关,在汽车尾部造型设计中,要尽量推迟尾部涡流的分离。
The turbulence field at the rear of the car is the main source of the pressure differential resistance. In the wind tunnel of the HD-2 model, the six-force and longitudinal symmetry of the car model under the condition of yaw angle are first used. The surface pressures at 48 measuring points were measured. Then the tail turbulence fields with yaw angles of 0 ° and 15 ° were measured by PIV measurement technique respectively. The velocity field, the vorticity Field and Reynolds stress flow field information, through calculating the wake flow field spatial correlation coefficient and turbulence integral scale. The results show that under the condition of yaw angle, the structure of the vortex at the tail of the automobile tends to develop upward. The range and intensity of the drag vortex in wake field lead to a large increase of the aerodynamic force. The turbulent integral scale The variation of the tail vortex area is related to the location of vortex shedding. In the design of the tail of the car, it is necessary to delay the separation of the tail vortex.