| By use of the numerical simulation and experimental method, the aerodynamic performance of the sail in the Olympic Games was studied and analyzed. The results of the research could supervise the athletes to trim the sails based on the condition.It's discussed how the district and grid of the numerical simulation could affect the precision of the results. If the district would be six times of the chord of the sail bottom on the ahead, left, right and up direction, ten times of the chord of the sail bottom and the grid would be mixed, the precision could be good and the time could be saved. It's discussed how the inlet modes affected the results. In this article, when the aerodynamic performance of the sail was studied by the numerical simulation, the inlet direction was immobile and the sail was turned, the grid of the district was constructed. The article studied how the turbulence model affected the precision of the results. Five different turbulence models were used on the sails. Based on the theoretical analysis and the compare with the experimental results, the realizable k -εmodel was the best in terms of the both accuracy and robustness, and this model was used to predict the aerodynamic performance of the sails. The difference of the flow field under the uniform and gradient wind was analyzed. It's found that there was different, but the difference was small between the uniform and gradient wind. Due to the practice condition, the gradient wind was used.The aerodynamic performance of two sails was discussed. It's found that the mast affected the aerodynamic performance of the sails obviously and the streamline mast should be used on the game. The different pitch of the sail affected the aerodynamic performance. If the sail was pitched with the direction of the athlete, the lift coefficient would decrease, but the upward force coefficient would enhance awfully. So, it would be propitious to decrease the resistance of the hull and enhance the speed of the sailing. The pitch with the direction of the stern would enhance the lift coefficient of the sails and the speed of the sailing. By compare with the aerodynamic performance of two sails, it's found that the lift coefficient would be bigger and the speed of the sailing would be enhanced, but the drag coefficient of the sail would also enhance if the camber ratio of the sail was higher. So, if the whole performance of the sail would be considered, the smaller camber ratio would be used on the strong wind and the bigger camber ration should be used on the light wind.The aerodynamic performance of the sail was studied by the experiment method in a wind tunnel. The data of the aerodynamic performance of the sail in different angle of the sailing were gained. The results were accordant with the practice.Based on the results of the numerical simulation and experimental method, the thrust and side force coefficients of two sails were compared. The good attack angle of the different sails was found.The trimming of the sail run through the process in the match, this article analysis the methods of the trimming during the leg of the starting, windward, downwind and the front of the finish line and the side of all the mark. The athletes should keep a firm grip on the principle of the whole leg and use them to trim the sail.The researches of the article have applied to supervise the testing and compete of the civil national sailing team and were contributed to get the copper brand and break through the brand of the civil sailing in the Olympic Games... |
