In this paper,a Double-stage Surrogate-based Shape Optimization(DSSO)strategy for Blended-Wing-Body Underwater Gliders(BWBUGs)is proposed to reduce the computational cost.In this strategy,a double-stage surrogate mode...In this paper,a Double-stage Surrogate-based Shape Optimization(DSSO)strategy for Blended-Wing-Body Underwater Gliders(BWBUGs)is proposed to reduce the computational cost.In this strategy,a double-stage surrogate model is developed to replace the high-dimensional objective in shape optimization.Specifically,several First-stage Surrogate Models(FSMs)are built for the sectional airfoils,and the second-stage surrogate model is constructed with respect to the outputs of FSMs.Besides,a Multi-start Space Reduction surrogate-based global optimization method is applied to search for the optimum.In order to validate the efficiency of the proposed method,DSSO is first compared with an ordinary One-stage Surrogate-based Optimization strategy by using the same optimization method.Then,the other three popular surrogate-based optimization methods and three heuristic algorithms are utilized to make comparisons.Results indicate that the lift-to-drag ratio of the BWBUG is improved by 9.35%with DSSO,which outperforms the comparison methods.Besides,DSSO reduces more than 50%of the time that other methods used when obtaining the same level of results.Furthermore,some considerations of the proposed strategy are further discussed and some characteristics of DSSO are identified.展开更多
A rapid method of the trim drag prediction for the blended-wing-body unmanned aerial vehicle(UAV)configuration is proposed.The method consists of four steps.The first step is to parameterizedly model the blended-wing-...A rapid method of the trim drag prediction for the blended-wing-body unmanned aerial vehicle(UAV)configuration is proposed.The method consists of four steps.The first step is to parameterizedly model the blended-wing-body UAV configuration;the second is to analyze the aerodynamics of the geometric model;the third is to create aerodynamic surrogate model;and the final step is to predict the trim drag using the surrogate model.Hence,a tool for trim drag prediction is developed by integration of the four steps.The impacts of the allocation of control surfaces,position of gravity center and planform parameters on the trim drag are investigated by using the tool.Results show that using the control surface in outer wing for trim has an advantage of lower trim drag,and the position of gravity center has a primary impact on the trim drag.Moreover,the planform has secondary impacts on the trim drag.展开更多
Blended-Wing-Body(BWB)aircraft is promoted as one of the most possible layouts to achieve more sustainable civil aviation.Due to the non-circular cross-section of the center-body,a bulge deformation forms over the upp...Blended-Wing-Body(BWB)aircraft is promoted as one of the most possible layouts to achieve more sustainable civil aviation.Due to the non-circular cross-section of the center-body,a bulge deformation forms over the upper surface of the body under the coupled loads of the internal pressurization of the cabin and the aerodynamic bending moments of the wing,which reduces the lift-to-drag ratio of BWB aircraft.Under a limited deformation,the relationship between the aerodynamic performance and the structural weight needs to be studied.In this work,the effects of stiffness constraints on the center-body deformation,structural weight of the airframe and aerodynamic performance were investigated by using an analytical model of the Pultruded Rod Stitched Efficient Unitized Structure(PRSEUS)for the airframe and the computational fluid dynamics method,respectively.The results show that as the stiffness constraint increases,the spacings between the rod stringers and the frame stiffeners decrease,and the structural weight increases inversely.A 5.2% reduction of the lift-to-drag ratio is encountered at cruise for a medium deformation design of 42.8 mm/m.A higher aerodynamic penalty is suffered when the stiffness constraint is further released.The final deformation criterion is different when the weight vector of the aerodynamic performance and structural weight is different.展开更多
基金This research was financially supported by the National Natural Science Foundation of China(Grant Nos.51875466 and 51805436)the China Postdoctoral Science Foundation(Grant No.2019T120941)the China Scholarships Council(Grant No.201806290133).
文摘In this paper,a Double-stage Surrogate-based Shape Optimization(DSSO)strategy for Blended-Wing-Body Underwater Gliders(BWBUGs)is proposed to reduce the computational cost.In this strategy,a double-stage surrogate model is developed to replace the high-dimensional objective in shape optimization.Specifically,several First-stage Surrogate Models(FSMs)are built for the sectional airfoils,and the second-stage surrogate model is constructed with respect to the outputs of FSMs.Besides,a Multi-start Space Reduction surrogate-based global optimization method is applied to search for the optimum.In order to validate the efficiency of the proposed method,DSSO is first compared with an ordinary One-stage Surrogate-based Optimization strategy by using the same optimization method.Then,the other three popular surrogate-based optimization methods and three heuristic algorithms are utilized to make comparisons.Results indicate that the lift-to-drag ratio of the BWBUG is improved by 9.35%with DSSO,which outperforms the comparison methods.Besides,DSSO reduces more than 50%of the time that other methods used when obtaining the same level of results.Furthermore,some considerations of the proposed strategy are further discussed and some characteristics of DSSO are identified.
基金supported by the National Defense Basic Scientific Research Program of China(No.A2520110006)the Fundamental Research Funds for the Central Universities(Nos.NJ20130001,NJ2012014)
文摘A rapid method of the trim drag prediction for the blended-wing-body unmanned aerial vehicle(UAV)configuration is proposed.The method consists of four steps.The first step is to parameterizedly model the blended-wing-body UAV configuration;the second is to analyze the aerodynamics of the geometric model;the third is to create aerodynamic surrogate model;and the final step is to predict the trim drag using the surrogate model.Hence,a tool for trim drag prediction is developed by integration of the four steps.The impacts of the allocation of control surfaces,position of gravity center and planform parameters on the trim drag are investigated by using the tool.Results show that using the control surface in outer wing for trim has an advantage of lower trim drag,and the position of gravity center has a primary impact on the trim drag.Moreover,the planform has secondary impacts on the trim drag.
基金supported partially by the National Key Laboratory Project,China(No.61422010201).
文摘Blended-Wing-Body(BWB)aircraft is promoted as one of the most possible layouts to achieve more sustainable civil aviation.Due to the non-circular cross-section of the center-body,a bulge deformation forms over the upper surface of the body under the coupled loads of the internal pressurization of the cabin and the aerodynamic bending moments of the wing,which reduces the lift-to-drag ratio of BWB aircraft.Under a limited deformation,the relationship between the aerodynamic performance and the structural weight needs to be studied.In this work,the effects of stiffness constraints on the center-body deformation,structural weight of the airframe and aerodynamic performance were investigated by using an analytical model of the Pultruded Rod Stitched Efficient Unitized Structure(PRSEUS)for the airframe and the computational fluid dynamics method,respectively.The results show that as the stiffness constraint increases,the spacings between the rod stringers and the frame stiffeners decrease,and the structural weight increases inversely.A 5.2% reduction of the lift-to-drag ratio is encountered at cruise for a medium deformation design of 42.8 mm/m.A higher aerodynamic penalty is suffered when the stiffness constraint is further released.The final deformation criterion is different when the weight vector of the aerodynamic performance and structural weight is different.
