Investigation On Aerodynamic Performance Of A Sail Wing At Different Wind Speeds Based On Dynamic Mesh

RS: X-class sailboard of wing is one of the official competitions of the Asian Games and the Olympic Games.Domestic and foreign scholars have done some research on the aerodynamic performance of the sail wings,but these studies generally do not consider the deformation of the sail wing due to the influence of aerodynamic performance.After the wind speed changes,the sail wing will also be deformed.Then,the deformation of the structure will cause the flow field to change.Therefore,we need to investigate the fluid-structure interaction of the sail wing at different wind speeds.We use two dynamic mesh methods,spring smoothing and local reconstruction method,to solve the next problem.In the case where the sail wing at 40°angle of attack and the flow velocity is 2m/s,4m/s,6m/s,8m/s,10m/s and 12m/s,we use both unidirectional and bidirectional fluid-structure coupling to discuss the aerodynamic performance of the sail wing.The distribution of the pressure on the windward and leeward sides of the sail wing,and the overall aerodynamic force of the sail wing and its variation rules were analyzed.Finally,the results of the sail wings calculated by unidirectional and bidirectional fluid-structure coupling methods was compared and analyzed.The results shows that with the increase of wind speed,the overall pressure change trend of the sail airfoil is stable,and the lift-drag coefficient and lift-drag ratio are the largest when the wind speed is 2m/s.As the increase of wind speed increases the stress area of the sail,the stress concentration is concentrated on the whole sail wing and the strain of the entire sail gradually increases,which also affects the entire flow field of the sail wing.Therefore,it is necessary to consider the coupling effect of the sail wing and the flow field.Through the bidirectional fluid-structure coupling calculation,it is found that the deformation of the sail wing is concentrated in the middle of the trailing edge of the sail wing,and the larger strain distribution is near the upper middle part of the mast and the middle of the tail edge of the sail wing.As the wind speed increases,the deformation of the sail surface increases,the deformation range also increases,and the corresponding strain area gradually becomes larger.The lift and drag coefficient of the sail wings at different wind speeds are compared using unidirectional and bidirectional fluid-structure coupling calculations.We find that the lift and drag coefficient obtained by the two coupling solution methods has the same trend with the change of wind speed,and the lift and drag coefficient is the maximum when the wind speed is 2m/s.By comparing the strain cloud images obtained by the two coupling solution methods,it is found that the strain maximum and the distribution area range are different,and the strain varies with the increase of the wind speed.In the bidirectional fluid-structure coupling analysis,because the data flow field and the structure are transmitted to each other as well as the calculated results take the effects of each other into account,so the strain and sail deformation obtained are closer to the actual situation.Considering the fluid-structure coupling,this research studies the aerodynamic performance of the sails at different wind speeds based on the dynamic mesh technique.The results provide a reference for the athletes to adjust the RS:X-class sails in training and actual competition,which can further improve the scientific training level of Chinese windsurfing.