Since the oil crisis of the last century, drag reduction for vehicles has become the focus of researchers. Currently the world’s major car brands have to seize the sport utility vehicle market. However, the sport utility vehicle models usually have a larger frontal area which brings challenges to drag reduction. This requires a better understanding of flow around sport utility vehicle models. The Motor Industry Research Association square-back vehicle model is similar to the sport utility vehicle geometry and can reflect the typical characteristics of aerodynamics of sport utility vehicle models. In this article, the wake flow structures of a 1/8 Motor Industry Research Association model is measured by particle image velocimetry. The results indicate that there is an obviously “n” type backflow vortex behind the vehicle. In the vertical direction, the vortex rotates from the outside to the inside, meanwhile the vortex rotates from the inside to the outside in the longitudinal direction. There is a velocity deficit region between the vortex and the back of the model which is an important source of drag force. This article summarizes the results of particle image velocimetry measurements from the model tests and obtains a picture of the structures of the wake vortex finally which can provide a theoretical basis for the drag reduction research in the future.

自上世纪的石油危机以来，减少车辆的阻力已成为研究人员关注的焦点。当前，世界主要汽车品牌必须抢占运动型多功能车市场。然而，运动型多功能车通常具有较大的前部面积，这给减阻带来了挑战。这就需要更好地了解越野车模型周围的流动。汽车工业研究协会的方后方车辆模型类似于越野车的几何形状，并且可以反映出越野车模型的空气动力学特性。在本文中，通过粒子图像测速仪测量了1/8汽车工业研究协会模型的尾流结构。结果表明，车辆后面存在明显的“ n”型回流涡流。在垂直方向上 涡流从外向内旋转，同时涡流在纵向上从内向外旋转。在涡旋和模型背面之间存在速度不足区域，这是阻力的重要来源。本文总结了模型测试中颗粒图像测速仪的测量结果，并最终获得了尾流涡流的结构图，可为今后减阻研究提供理论依据。