| With the improvement of the high-speed train in our country, aerodynamics has become an important problem. The air resistance is bounded up with the shape of the train. Therefore, Drag reduction by changing the shape of the high-speed train has been the focus of the research. Applying the theory of bionics design and the method of numerical simulation, the non-smooth surface elements have been added to the surface of the car body. The performance of the drag reduction on the non-smooth surface has been studied. The main work of this paper is as follows:(1) By making reasonable simplification of non-smooth surface in biology, the pit shape of the non-smooth body surface unit is obtained. By using three-dimensional modeling software Rhinoceros, the non-smooth train model is set up, and then the simulation calculation is completed by CFD software STAR-CCM+.(2) By making the non-smooth body cells of different sizes arranged in the relevant location of the vehicle body, the non-smooth aerodynamic model is calculated, and the resistance between smooth and non-smooth model is compared, and then the most suitable position of non-smooth surface of the unit body is found.(3) The pressure drag, viscous drag, the surface velocity and the turbulence intensity of the smooth and non-smooth train are compared in the paper. The principle of the aerodynamic drag reduction on the non-smooth surface has been further analyzed, so as to providing a theoretical basis for reducing the aerodynamic drag on non-smooth surface.In this paper, the model of non-smooth surface of the train can be derived:(1) No matter how the shape of the model changes, the position that non-smooth unit is arranged around the streamlined the place is not the best.(2) It has a good drag reduction effect that making the pit type non-smooth surface of the unit arranged in the wall of the train bogie. The arrangement of the pit type non-smooth surface of the unit body has a great influence on the drag reduction. |
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