Optimization For Diamond Wing Aircraft Aerodynamic Configuration

Diamond wing configuration,as an unconventional aerodynamic configuration,has unique advantages in aerodynamic characteristics,structural characteristics and maneuverability.However,the design of diamond wing configuration faces a lot challenges because of the unique shape of diamond wing aircraft.Firstly,an optimization design system for diamond wing configuration was established using the Tornado and the modeFRONTIER.The design system takes maximum lift-drag ratio as target,adopts vortex lattice method and optimization method to optimize the aerodynamic configuration of diamond wing aircraft.Six groups of aerodynamic configuration of diamond wing aircraft were conducted after optimization and the correlations between geometric parameters(spans,root chords,dihedrals,sweep angles and taper ratio)and aerodynamic characteristics of diamond wing aircraft were summarized.The analysis of these correlations can provide suggestions and references for the preliminary design of diamond wing aircraft.Secondly,DLR-F6 model was simulated using the computational fluid dynamics software Fluent and three different turbulence models.After comparing the results with the wind tunnel experimental data,the Realizable k-? model was chosen as the turbulence model for the further numerical simulation.Then the DLR-F6 was enlarged to a scale similar to that of the diamond wing aircraft,and three different meshes were created.Based on the Realizable k-? model,the models were simulated and analyzed to determine the appropriate number of meshes and mesh distribution.The validation of this part of numerical simulation lays a foundation for the numerical simulation of diamond wing aircraft.Finally,the six models of diamond wing aircraft were quickly modeled and 3d numerical simulations were carried out.According to the calculation results of each case at 0°,5°,10° and 15° angles of attack.One case was selected as the optimal diamond wing configuration from 6 cases and the reasons for selecting this configuration as the optimal configuration were summarized:Under the condition of 5°Angle of attack,the lift-to-drag ratio of the optimal case can reach 22.0761;In the state of 10°and 15° angle of attack,the flow field between the Front-wing and After-wing of diamond wing aircraft becomes complicated due to the mutual interference between the up-wash airflow of the Front-wing and the down-wash airflow of the After-wing;Due to the large relatively distance between the Front-wing and After-wing of the optimal case,the wake flow of the Front-wing has relatively little interference with the After-wing,which makes the optimal case have better aerodynamic characteristics under the condition of large angle of attack.The aerodynamic configuration optimization platform for diamond wing aircraft established in this paper can be used not only for aerodynamic configuration optimization of diamond wing aircraft,but also for preliminary design of other aircraft and other related fields.