Pressure distribution is important information for engineers during an aerodynamic design process. Pressure Distribution Oriented(PDO) optimization design has been proposed to introduce pressure distribution manipulat...Pressure distribution is important information for engineers during an aerodynamic design process. Pressure Distribution Oriented(PDO) optimization design has been proposed to introduce pressure distribution manipulation into traditional performance dominated optimization.In previous PDO approaches, constraints or manual manipulation have been used to obtain a desirable pressure distribution. In the present paper, a new Pressure Distribution Guided(PDG) method is developed to enable better pressure distribution manipulation while maintaining optimization efficiency. Based on the RBF-Assisted Differential Evolution(RADE) algorithm, a surrogate model is built for target pressure distribution features. By introducing individuals suggested by suboptimization on the surrogate model into the population, the direction of optimal searching can be guided. Pressure distribution expectation and aerodynamic performance improvement can be achieved at the same time. The improvements of the PDG method are illustrated by comparing its design results and efficiency on airfoil optimization test cases with those obtained using other methods. Then the PDG method is applied on a dual-aisle airplane’s inner-board wing design. A total drag reduction of 8 drag counts is achieved.展开更多
Flows around vortex generators(VGs),which serve as one of the important flow control methods,are investigated by solving Reynolds-averaged Navier-Stokes(RANS)equations.The influences on the main flow of VGs are intend...Flows around vortex generators(VGs),which serve as one of the important flow control methods,are investigated by solving Reynolds-averaged Navier-Stokes(RANS)equations.The influences on the main flow of VGs are intended to explore.Firstly, the flow around a single VG on a flat plane is computed to validate the schemes and to acquire basic knowledge of this kind of flow.Secondly,transonic flow past a standard model,named by ONERA-M6 wing,is predicted to investigate the flow features of shockwave/boundary-layer interactions(SWBLI).Thirdly,the effects of a row of VGs mounted about 25%local chord on a supercritical wing are analyzed in transonic condition with strong SWBLI.Lastly,VGs are mounted more upwind(about 3.5%local chord)to explore the effects at low speed and high incidence condition.The numerical results show that seven VGs can effectively suppress the separations behind the strong SWBLI and decrease spanwise flow and wing-tip vortex in transonic condition.VGs also can decrease the large scope of separation over the wing at low speed with high angle of attack.展开更多
Variable-camber technology is considered an effective way to adaptively improve the aerodynamic performance of aircraft under various flight conditions.This paper studies the aerodynamic characteristics of the trailin...Variable-camber technology is considered an effective way to adaptively improve the aerodynamic performance of aircraft under various flight conditions.This paper studies the aerodynamic characteristics of the trailing-edge variable-camber technology by means of Computational Fluid Dynamics(CFD)and a drag decomposition method.Trailing-edge variable-camber technology can be simply realized by the continuous deflection of the flaps and ailerons of a wing.A supercritical airfoil is used to study the two-dimensional effect of variable-camber technology,and a wide-body airplane model is used to validate the three-dimensional improvement in the wing’s airfoil made by variable-camber technology.An optimization strategy for airfoil that incorporates variable-camber technology is proposed.The optimization results demonstrate that the proposed method can obtain better results than the traditional segregated shape optimization.展开更多
Shock control bumps are a promising technique in reducing wave drag of civil transport aircraft flying at transonic speeds.This paper investigates the optimization of 3D shock control bumps on a supercritical wing wit...Shock control bumps are a promising technique in reducing wave drag of civil transport aircraft flying at transonic speeds.This paper investigates the optimization of 3D shock control bumps on a supercritical wing with a sweep angle of 16°at the1/4 chord.A similar supercritical wing with a higher sweep angle of 24.5°at the 1/4 chord has been adopted as a baseline for the study.Numerical results show that the drag coefficient of the low sweep wing with the optimized 3D shock control bumps is reduced below that for the high sweep wing,indicating shock control bumps can be used as an effective means to reduce the wave drag caused by reducing the wing sweep angle.From the point of view of the wing structure design,lower sweep angle will also bring the benefits of weight reduction,resulting in further fuel reduction.展开更多
基金co-supported by the National Key Basic Research Program of China(No.2014CB744806)Tsinghua University Initiative Scientific Research Program(No.2015Z22003)
文摘Pressure distribution is important information for engineers during an aerodynamic design process. Pressure Distribution Oriented(PDO) optimization design has been proposed to introduce pressure distribution manipulation into traditional performance dominated optimization.In previous PDO approaches, constraints or manual manipulation have been used to obtain a desirable pressure distribution. In the present paper, a new Pressure Distribution Guided(PDG) method is developed to enable better pressure distribution manipulation while maintaining optimization efficiency. Based on the RBF-Assisted Differential Evolution(RADE) algorithm, a surrogate model is built for target pressure distribution features. By introducing individuals suggested by suboptimization on the surrogate model into the population, the direction of optimal searching can be guided. Pressure distribution expectation and aerodynamic performance improvement can be achieved at the same time. The improvements of the PDG method are illustrated by comparing its design results and efficiency on airfoil optimization test cases with those obtained using other methods. Then the PDG method is applied on a dual-aisle airplane’s inner-board wing design. A total drag reduction of 8 drag counts is achieved.
基金supported by the National Natural Science Foundation of China(Grant No.10932005)
文摘Flows around vortex generators(VGs),which serve as one of the important flow control methods,are investigated by solving Reynolds-averaged Navier-Stokes(RANS)equations.The influences on the main flow of VGs are intended to explore.Firstly, the flow around a single VG on a flat plane is computed to validate the schemes and to acquire basic knowledge of this kind of flow.Secondly,transonic flow past a standard model,named by ONERA-M6 wing,is predicted to investigate the flow features of shockwave/boundary-layer interactions(SWBLI).Thirdly,the effects of a row of VGs mounted about 25%local chord on a supercritical wing are analyzed in transonic condition with strong SWBLI.Lastly,VGs are mounted more upwind(about 3.5%local chord)to explore the effects at low speed and high incidence condition.The numerical results show that seven VGs can effectively suppress the separations behind the strong SWBLI and decrease spanwise flow and wing-tip vortex in transonic condition.VGs also can decrease the large scope of separation over the wing at low speed with high angle of attack.
基金supported by the National Natural Science Foundation of China(Nos.11872230 and 91852108)。
文摘Variable-camber technology is considered an effective way to adaptively improve the aerodynamic performance of aircraft under various flight conditions.This paper studies the aerodynamic characteristics of the trailing-edge variable-camber technology by means of Computational Fluid Dynamics(CFD)and a drag decomposition method.Trailing-edge variable-camber technology can be simply realized by the continuous deflection of the flaps and ailerons of a wing.A supercritical airfoil is used to study the two-dimensional effect of variable-camber technology,and a wide-body airplane model is used to validate the three-dimensional improvement in the wing’s airfoil made by variable-camber technology.An optimization strategy for airfoil that incorporates variable-camber technology is proposed.The optimization results demonstrate that the proposed method can obtain better results than the traditional segregated shape optimization.
基金supported by a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions of China
文摘Shock control bumps are a promising technique in reducing wave drag of civil transport aircraft flying at transonic speeds.This paper investigates the optimization of 3D shock control bumps on a supercritical wing with a sweep angle of 16°at the1/4 chord.A similar supercritical wing with a higher sweep angle of 24.5°at the 1/4 chord has been adopted as a baseline for the study.Numerical results show that the drag coefficient of the low sweep wing with the optimized 3D shock control bumps is reduced below that for the high sweep wing,indicating shock control bumps can be used as an effective means to reduce the wave drag caused by reducing the wing sweep angle.From the point of view of the wing structure design,lower sweep angle will also bring the benefits of weight reduction,resulting in further fuel reduction.
