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Multi-objective optimization of shock control bump on a supercritical wing

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Science China(Technological Sciences) 2014年第1期57卷 192-202页

作者： TIAN Yun liu peiqing LI Zhi School of Aeronautical Science and Engineering Beihang University

Based on the supercritical ＂wingl＂ which was released in the DPW-III conference, multi-objective optimization has been done to increase the lift-drag ratio at cruise condition and improve transonic buffet boundary and drag-rise performance. Hicks-Henne shape functions are used to represent the bump shape. In the design optimization to increase lift-drag ratio, the objectives involve the cruise point and three other off-design points nearby. In the other optimization process to improve buffet and drag-rise performance, three buffet onset points near the cruise point and one drag-rise point are selected as the design points. Non-dominating sort genetic algorithm II （NSGA-II） is used in both processes. Additionally, individual analysis for every selected point on the Pareto frontier is conducted in order to avoid local convergence and achieve global optimum. Re- sults of optimization for aerodynamic efficiency show a decrease of 11 counts in drag at the cruise point. Drag at nearby off-design points are also reduced to some extent. Similar approaches are made to improve buffet and drag-rise characteristics, resulting in significant improvements in both ways.

关键词： shock control bump lift-drag ratio buffet drag-rise characteristics flow control

Numerical simulation of heat transfer of latent functionally thermal fluid in tubes with coaxially inserted cylindrical bars in laminar

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Science China(Technological Sciences) 2008年第8期51卷 1232-1241页

作者： JIN Jian liu peiqing LIN GuiPing School of Aeronautical Science and Engineering Beihang UniversityBeijing 100083China

The heat transfer of latent functionally thermal fluid in three kinds of tubes with coaxially inserted cylindrical bars is numerically researched using equivalent spe- cific heat model, and the flow fields are analyzed with field synergy field. It is found that in the tubes with coaxially inserted cylindrical bars, the heat transfer effects of functionally thermal fluid become more and more pronounced with the Ste de- creasing. This is similar to be case of functionally thermal fluid flowing in smooth straight tubes. Compared with the results receiving from smooth straight tubes, the heat transfer of functional thermal fluid in tubes with coaxially inserted cylindrical bars has been significantly enhanced. And this effect becomes more apparent as the diameter of coaxially inserted cylindrical bars increases meanwhile, however, energy consuming of the tubes shows the same trend.

关键词： latent functionally thermal fluid field synergy equivalent heat specific microencapsulated phase change material

Transonic buffet control research with two types of shock control bump based on RAE2822 airfoil

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Chinese Journal of Aeronautics 2017年第5期30卷 1681-1696页

作者： Yun TIAN Shiqi GAO peiqing liu Jinjun WANG National Lab for Aeronautics and Astronautics Beihang University Beijing 100191 China School of Aeronautic Science and Engineering Beihang University Beijing 100191 China

Current research shows that the traditional shock control bump（SCB） can weaken the intensity of shock and better the transonic buffet performance. The author finds that when SCB is placed downstream of the shock, it can decrease the adverse pressure gradient. This may prevent the shock foot separation bubble to merge with the trailing edge separation and finally improve the buffet performance. Based on RAE2822 airfoil, two types of SCB are designed according to the two different mechanisms. By using Reynolds-averaged Navier-Stokes（RANS） and unsteady Reynolds-averaged Navier-Stokes（URANS） methods to analyze the properties of RAE2822 airfoil with and without SCB, the results show that the downstream SCB can better the buffet performance under a wide range of freestream Mach number and the steady aerodynamics characteristic is similar to that of RAE2822 airfoil. The traditional SCB can only weaken the intensity of the shock under the design condition. Under the off-design conditions, the SCB does not do much to or even worsen the buffet performance. Indeed, the use of backward bump can flatten the leeward side of the airfoil, and this is similar to the mechanism that supercritical airfoil can weaken the recompression of shock wave.

关键词： Aerodynamics Buffet control RAE2822 airfoil Shock control bump Transonic

Shock control bump parametric research on supercritical airfoil

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Science China(Technological Sciences) 2011年第11期54卷 2935-2944页

作者： TIAN Yun liu peiqing FENG PeiHua School of Aeronautics Science and Engineering Beihang University Beijing 100191 China

High precision of CFD code was used to study supercritical Airfoil RAE2822 superimposed with different shock control bumps under the transonic conditions.A successful improvement was made to current widely used Hicks-Henne functions which describe shock control *** on improving the airfoil's lift-drag ratio,the study shows that,(1) the best bump crest position is at the position close to 50% of bump chord,which is almost independent of free stream or pre-shock Mach numbers,but the bump height is highly coupled with the crest position,which means that the higher the bump is,the more obviously the crest position affects the airfoil lift-drag ratio,and it becomes more evident with the increase of free stream or pre-shock Mach numbers;(2) in case that the lift-drag ratio of airfoil with bump is higher than basic airfoil,almost all the optimum distances between bump crest and shock wave are close to 30% of bump chord;(3) almost all the lift-drag ratios of airfoil with bump increase as bump chord length increases,of which this trend becomes more evident as bump height increases;(4) with the increase of the bump height,almost all the lift-drag ratios of airfoil with bump decrease at low free stream or pre-shock Mach *** the Mach numbers are higher,the lift-drag ratio of airfoil increases as the increase of the bump height,and particularly,the trend tends to be visible when the Mach numbers are at a high level.

关键词： shock wave flow control transonic flow parametric supercritical airfoil

Aerodynamic/mechanism optimization of a variable camber Fowler flap for general aviation aircraft

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Science China(Technological Sciences) 2017年第8期60卷 1144-1159页

作者： TIAN Yun WANG Tao liu peiqing FENG PeiHua National Lab for Aeronautics and Astronautics Beijing 100191 China COMAC Shanghai Aircraft Customer Service Co. Ltd Shanghai 200241 China School of Aeronautic Science and Engineering Beihang University Beijing 100191 China Beijing Machinery and Electronics Engineering Institute Beijing 100074 China

A conventional Fowler flap is designed to improve the take-off and landing performances of an aircraft. Because the flight states of general aviation aircraft vary significantly. A Fowler flap with a double-sliding track has been designed, which is ca- pable of changing airfoil camber while cruising and climbing as well as meeting low-speed performance requirements. The aerodynamic characteristics of the variable camber Fowler flap were studied by computational simulation, and cambering was found to be beneficial for improving the lift-to-drag ratio when the lift coefficient was larger than the critical value, below which decambering was more effective; this critical value differed somewhat under different conditions. Taking the mecha- nism into account, the take-off and landing configurations were optimized on the basis of the GA （W）-1 airfoil with a 30% chord Fowler flap. Compared with reference configuration, the maximum lift coefficient of optimized take-off configuration was increased by 6.6% as well as the stalling angle and the lift-to-drag ratio were increased by 1.3° and 7.58%, respectively. Moreover, the maximum lift coefficient of the optimized landing configuration was increased by 6.3%, and the stalling angle was increased by 1.1°; however, the nose-down pitching moment of both configurations increased. Similar results were at- rained on a general aviation aircraft wing/body combination nism was established in a computer-aided design system, achieved by the double-sliding track. A 3D model of the variable-camber Fowler flap driving mecha- and the results showed that all design configurations could be

关键词： Fowler flap general aviation aircraft variable camber optimization

Effect of pitch angle on initial stage of a transport airplane ditching

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Chinese Journal of Aeronautics 2013年第1期26卷 17-26页

作者： Guo Baodong liu peiqing Qu Qiulin Wang Jiawen Institute of Fluid Mechanics Beihang University Key Laboratory of Fluid Mechanics Ministry of Education Beihang University

Airworthiness regulations require that the transport airplane should be proved to ensure the survivability of the ditching for the passengers. The planned ditching of a transport airplane on the calm water is numerically simulated. The effect of pitch angle on the impact characteristics is especially investigated by a subscaled model. The Reynolds-averaged Navier-Stokes （RANS） equations of unsteady compressible flow are solved and the realizable j-e equations are employed to model the turbulence. The transformation of the air-water interface is tracked by volume of fluid （VOF） model. The motion of the rigid body is modeled by dynamic mesh method. The initial ditching stage of the transport airplane is analyzed in detail. The numerical results show that as the pitching angle increases, the maximal normal force decreases and the pitching motion becomes much gentler. The aft fuselage would be sucked down by the water and lead to pitching up, whereas the low horizontal tail prevents this trend. Consequently, the transport aircraft with low horizontal tail should ditch on the water at an angle between 10 and 12 as a recommendation.

关键词： Crashworthiness Fluid structure interaction Hydrodynamics Multiphase flow Transport aircraft Water landing

Attractive fixed-point solution study of a shell model for turbulent convection

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Science China(Physics,Mechanics & Astronomy) 2013年第5期56卷 995-1003页

作者： GUO Hao LI Chao QU QiuLin liu peiqing Institute of Fluid Mechanics Beihang University Key Laboratory of Fluid Mechanics (Beihang University) Ministry of Education

Different scaling behaviors, such as Kolmogorov (K41) scaling and Bolgiano and Obukhov (BO) scaling, have been reported in various shell models proposed for turbulent thermal convection. However, two coexistent subranges with K41 and BO scaling are not set up with Bolgiano scale interlaying between the largest scale and the dissipation scale. In this paper, we summarize fixed-point solution study of the Brandenburg model with small perturbation theory by introducing a small disturbance term as the impact of buoyancy. Three groups of fixed-point solutions with different locations of the so-called buoyancy scale, above/below which buoyancy is significant/insignifant. Both theoretical and numerical results show that a modified K41 scaling, instead of K41 and BO coexistent scaling, is set up even though buoyancy may be significant over the scaling range, which suggests that the buoyancy scale is not related exactly to the Bolgiano scale. Thus, a K41 and BO coexistent scaling behavior is not setup for the Brandenburg model.

关键词： turbulent convection shell model fixed-point scaling behavior

Generation of spatial atmospheric turbulence field in aircraft motion simulation based on refined similarity hypothesis

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Science China(Technological Sciences) 2011年第1期54卷 244-250页

作者： GUO Hao CHEN JingJing QU QiuLin liu peiqing Institute of Fluid Mechanics Beihang University and Key Laboratory of Fluid Mechanics (Beihang University) of Ministry of Education Beijing 100191 China

It is necessary to build turbulence model to study the response of aircraft to atmospheric turbulence for high resolution earth observation. The conventional method is on the basis of Dryden’s model with the assumption that individual patches are Gaussian. In this paper,based on Kraichnan’s refined similarity idea,a new 1D atmospheric turbulence model is set up by introducing the energy transfer rate as an intermittency disturbance to a Gaussian process. Our results show that the turbulent fields generated by our new method exhibit an anomalous scaling described by the She-Leveque (SL) formula,which is now well accepted for homogenous and isotropic turbulence.

关键词： aircraft motion simulation atmospheric turbulence ref'med similarity hypothesis energy transfer rate

Editorial of Special Column “Research on Emerging COVID-19(Target, Mechanism, and Therapeutics)”

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Acta Pharmaceutica Sinica B 2020年第7期10卷 1146-1148页

作者： Hai-Bin Luo Shilin Chen peiqing liu School of Pharmaceutical Sciences Sun Yat-sen UniversityGuangzhou 510006China Institute of Chinese Materia Medica China Academy of Chinese Medical SciencesBeijing 100700China Laboratory of Pharmacology&Toxicology and New Drug R&D Center School of Pharmaceutical SciencesSun Yat-Sen UniversityGuangzhou 510006China

Coronavirus disease 2019(COVID-19)pandemic caused by severe acute respiratory syndrome coronavirus 2(SARS-Co V-2)has become a global crisis1,*** from SARS-Co V-2 can result in severe lymphopenia,prolonged coagulation profiles,lethal acute respiratory distress syndrome(ARDS),watery diarrhea,cardiac disease,multiorgan dysfunction,and sudden death3,4.

关键词： acute respiratory distress