为了获得地面效应对汽车模型气动阻力的影响,在中国空气动力研究与发展中心Φ3.2m风洞对1∶3的MIRA汽车模型进行了风洞试验,采用移动带作为统一的研究平台,研究了地面静止与运动,车轮静止与旋转,以及车身不同离地间隙对气动阻力的影响;模拟了横摆角为0°的无侧风工况,固定试验风速为25m·s~(-1),变雷诺数试验风速为15~26m·s~(-1);仅对汽车模型进行气动力测量,主要关注气动阻力,试验结果以量纲为1的气动阻力系数表示。分析结果表明:当静止地面边界层厚度与车身底面离地间隙之比不大于0.32,且车轮下表面与车身底面离地间隙之比(定义为量纲为1的离地间隙)不大于0.37时,静止地面比运动地面的气动阻力略小,差异小于1.1%,因此,可以忽略地面状态对气动阻力的影响;车轮静止比车轮旋转下的气动阻力略小,差异小于2.1%,因此,在工程应用中,当不能模拟车轮旋转时,应考虑修正(增加)气动阻力,但修正量不宜大于2.1%;随着车轮下表面离地间隙的增加,气动阻力总体呈现逐渐减小的趋势,且在量纲为1的离地间隙为0.069~0.370时,气动阻力差异小于2.0%,因此,在采用移动带开展汽车模型风洞试验时,在确保车轮不与移动带带面接触的情况下,车轮下表面到带面间隙应尽可能小。 In order to obtain the effect of ground effect on the aerodynamic drag of the automobile model, a wind tunnel test was conducted on a 1: 3 MIRA car model at a Φ3.2 m wind tunnel at China Aerodynamics Research and Development Center using a moving belt as a unified research platform Ground static motion and motion, wheel static and rotation, and the influence of different ground clearances on the aerodynamic drag of the vehicle body. The cross-wind condition with yaw angle of 0 ° is simulated, the wind speed of fixed test is 25m · s -1, Reynolds number of test wind speed of 15 ~ 26m · s ~ (-1); only aerodynamic measurements of the car model, the main concern aerodynamic drag, the test results to a dimension of 1 aerodynamic drag coefficient said. The results show that when the ratio of the thickness of the stationary ground boundary layer to the ground clearance of the underbody is not more than 0.32 and the ratio of the under surface of the wheel to the ground clearance of the underbody (defined as ground clearance of dimension 1) is not greater than 0.37 , The aerostatic resistance of the static ground is slightly smaller than that of the moving ground, and the difference is less than 1.1%. Therefore, the influence of the ground state on the aerodynamic resistance can be neglected. The aerostatic resistance of the wheel at rest is slightly smaller than that under the rotation of the wheel, and the difference is less than 2.1% In application, the aerodynamic drag should be considered (increased) when the rotation of the wheel can not be simulated, but the correction should not be more than 2.1%. With the increase of the ground clearance of the lower surface of the wheel, the aerodynamic drag tends to decrease gradually, When the ground clearance of dimension 1 is 0.069 ~ 0.370, the difference of aerodynamic drag is less than 2.0%. Therefore, when the moving belt is used to carry out the wind tunnel test of the automobile model, when the wheel is not contacted with the moving belt, The lower surface to the gap should be as small as possible.