Simulation Analysis for Effect of Rear Structure of Hatchback Car on Rear Field Characteristics

The tail shape of the hatchback car is crucial to the rear field. To improve the tail aerodynamic design of the hatchback car, the orthogonal optimization method is used to reveal the rule of different tail structures affecting the aerodynamic drag and lift force considering their interference with each other. First, the different tail structures, such as the top, the side, the bottom and the tail structures, are analysed to reveal the influence of the wake based on the MIRA model. Then, the orthogonal optimization method is applied to investigate the tail shape optimal design considering the mutual influence of each tail structure. The aerodynamic drag coefficient and the lift coefficient are calculated to evaluate the aerodynamic characteristics in the orthogonal analysis. The results show that the angles of the rear windshield and the diffuser has a great influence on the aerodynamic drag. While the diffuser angle have the greatest influence on the lift coefficient. The influence of the rear windshield angle and roof angle is also noteworthy. In a word, the diffuser angle, the rear windshield angle and the roof angle are the key structures for the aerodynamic optimization of the tail of hatchback cars.