• <tr id="yyy80"></tr>
  • <sup id="yyy80"></sup>
  • <tfoot id="yyy80"><noscript id="yyy80"></noscript></tfoot>
  • 99热精品在线国产_美女午夜性视频免费_国产精品国产高清国产av_av欧美777_自拍偷自拍亚洲精品老妇_亚洲熟女精品中文字幕_www日本黄色视频网_国产精品野战在线观看 ?

    Numerical Optimization on Aerodynamic/Stealth Characteristics of Airfoil Based on CFD/CEM Coupling Method

    2016-09-05 08:56:33JiangXiangwenZhaoQijunZhaoGuoqingMengChen

    Jiang Xiangwen, Zhao Qijun, Zhao Guoqing, Meng Chen

    National Key Laboratory of Science and Technology on Rotorcraft Aeromechanics,Nanjing University of Aeronautics and Astronautics,Nanjing 210016,P.R.China

    (Received 16 May 2015; revised 18 July 2015; accepted 25 July 2015)

    Numerical Optimization on Aerodynamic/Stealth Characteristics of Airfoil Based on CFD/CEM Coupling Method

    Jiang Xiangwen, Zhao Qijun*, Zhao Guoqing, Meng Chen

    National Key Laboratory of Science and Technology on Rotorcraft Aeromechanics,Nanjing University of Aeronautics and Astronautics,Nanjing 210016,P.R.China

    (Received 16 May 2015; revised 18 July 2015; accepted 25 July 2015)

    Based on computational fluid dynamics (CFD)/computational electromagnetics method (CEM) coupling method and surrogate model optimization techniques, an integration design method about aerodynamic/stealth characteristics of airfoil is established. The O-type body-fitted and orthogonal grid around airfoil is first generated by using the Poisson equations, in which the points per wave and the normal range satisfy the aerodynamic and electromagnetic calculation accuracy requirement. Then the aerodynamic performance of airfoil is calculated by solving the Navier-Stokes (N-S) equations with Baldwin-Lomax (B-L) turbulence model. The stealth characteristics of airfoil are simulated by using finite volume time domain (FVTD) method based on the Maxwell′s equations, Steger-Warming flux splitting and the third-order MUSCL scheme. In addition, based upon the surrogate model optimization technique with full factorial design (FFD) and radial basis function (RBF), an integration design about aerodynamic/stealth characteristics of rotor airfoil is conducted by employing the CFD/CEM coupling method. The aerodynamic/stealth characteristics of NACA series airfoils with different maximum thickness and camber combinations are discussed. Finally, by choosing suitable lift-to-drag ratio and radar cross section (RCS) amplitudes of rotor airfoil in four important scattering regions as the objective function and constraint, the compromised airfoil with high lift-to-drag ratio and low scattering characteristics is designed via systemic and comprehensive analyses.

    rotor airfoil; aerodynamic characteristics; stealth characteristics; CFD/CEM coupling; surrogate model

    0 Introduction

    The selection of rotor airfoil not only affects aerodynamic characteristics of the helicopter directly, but also is the key to reduce radar cross section (RCS) characteristics of the armed helicopter rotor. Currently, the integrated optimization analyses about aerodynamic and stealth design of advanced helicopter rotor are an important trend. Therefore the integrated analyses about aerodynamic and stealth characteristics of rotor airfoil are a challenging multidisciplinary design optimization (MDO) issue.

    With the great improvements in computational fluid dynamics (CFD) method, computational electromagnetics method (CEM) and optimization algorithms, integrated analyses about aerodynamic/stealth characteristics of airfoil are becoming more and more feasible in modern MDO rotor design. The CFD technology has been widely used in rotor airfoil aerodynamic analyses and designs during the past decade[1]. Based on CFD technology, the finite volume time domain (FVTD) method was established for solving radar scattering problem. The FVTD method was first applied to calculate electromagnetic characteristics of targets by Shankar[2]in the 1980s, Camberos[3]developed COBRA software by Steger-Warming flux discretization combined with the four-stage Runge-Kutta time scheme, which can handle some simple targets. In recent years, high precision FVTD method has been preliminarily used in some complex targets[4-5]. In the integrated investigation of airfoil, Hoang Vinh[6]and Zhu[7]coupled CFD ( full-potential or Euler equations) with CEM method to conduct the preliminary MDO of airfoil.

    At present, some integrated research of wing airfoil mainly focuses on calculating its aerodynamic characteristics with reduced order models, and then find the optimal airfoils with specified constraint condition (RCS of airfoil leading edge) in the optimization methods. The motions of helicopter rotor blade include rotating, pitching and flapping. Therefore the rotor blades work in extraordinary and seriously unsteady environment compared with the fixed-wing aircraft in flight, and the aerodynamic characteristics of rotor airfoil are very complex such as shock waves on the advancing blade tip and separated flow regions at the retreating side. Meanwhile, the electromagnetic scattering characteristics about leading edge, upside, downside and trailing edge are all important for the rotor airfoil. So the integrated analyses about aerodynamic and stealth must take into account four important scattering regions of airfoil, which are conducive to rotor stealth design of armed helicopter.

    To develop a high precision computational method that can be used in MDO design of rotor airfoil, an integration design based CFD/CEM coupling method is proposed to predict aerodynamics/stealth characteristics of airfoil in this paper. In order to satisfy practice needs, NACA airfoils which are widely used in aviation are selected as baseline airfoils. The O-type aerodynamic/RCS computational grids are generated by solving Poisson equations. The airfoil aerodynamics/stealth characteristics are simulated by high precision CFD/ FVTD methods. Then an integration design about CFD/CEM coupling method is developed by optimization surrogate model technique. Additionally, the aerodynamic and stealth characteristics of NACA series airfoils with different maximum thickness and camber combinations are discussed. Finally, choosing suitable objective function and constraint condition about lift-to-drag ratio and RCS amplitudes of rotor airfoil at four important scattering regions, the rotor airfoil with high lift-to-drag ratio and low scattering characteristics is designed after comprehensive analyses.

    1 Computational Methods

    1.1Grid generation techniques

    The O-type body-fitted and orthogonal grids around rotor airfoil are generated by using Poisson equations. The grids around airfoil are shown in Fig.1. The aerodynamic/stealth computational grid contains 300×70 points, among which 150 points are on the lower and upper surfaces of the airfoil respectively, and 70 points in the direction normal to the airfoil′s surface. The four important scattering regions of rotor airfoil are leading edge (150°≤ψ≤210°), upside (60°≤ψ≤120°), downside (240°≤ψ≤300°) and trailing edge (-30°≤ψ≤30°), respectively.

    Fig.1 Computational grids around NACA0012 airfoil

    1.2CFD method

    The airfoil flowfield characteristics are calculated by Navier-Stokes (N-S) equations with Baldwin-Lomax (B-L) turbulence model which is based on the previous work[8-9].

    The N-S equations in integral form can be written as where x and y are the Cartesian coordinates, U the vector of conserved variables, F, G the inviscid fluxes, and Fv,Gvthe viscous fluxes.

    (1)

    (2)

    where ρ,P and Efare the density, pressure and total energy per unit mass, respectively, k the air heat transmission factor, τ the viscous related items, μf=μlf+μtf. μfis the coefficient of viscosity, μlfand μtfthe laminar flow and turbulent flow coefficient of viscosity respectively.

    Spatial discretization is conducted by the central difference scheme, and time discretization is conducted by the four-stage Runge-Kutta method. Boundary conditions are the non-reflection[10]. The viscous effect is calculated by using B-L turbulent model with strong robustness and high reliability, and the turbulent model can effectively simulate the attached flow and medium separation flow.

    1.3CEM method

    1.3.1Governing equations

    Maxwell′s equations in the differential form for wave propagation in free space can be expressed as

    (3)

    where B is the magnetic induction, E the electric field vector, D the electric field displacement, and H the magnetic field vector. B=μH, μ is the magnetic permeability, and D=εE, ε is the electric permittivity. The above equations are applied to every finite-volume cell in the grid. The integral form can be written as

    (4)

    1.3.2Discretization of equations

    The combination of third-order MUSCL scheme and Steger-Warming[11]flux-vector splitting algorithm were derived to solve Maxwell′s equations in conservative form. The spatial discretized formulation for the cell is

    (5)

    The four-stage Runge-Kutta method is also used for the temporal discretization.

    1.3.3Boundary conditions

    For a perfect electrically conducting (PEC) body, the boundary conditions[12]of the electric and magnetic fields are required, respectively, as where superscript ″t″ denotes total of the incident and scattered fields, and n denotes the outward unit normal vector.

    (6)

    1.3.4RCS evaluation

    The frequency-domain field can be transformed from the time-domain electromagnetic field by Fourier transform, and the RCS is solved by near-far field conversion. Radar scattering is calculated as where σ is the radar cross section and R0the distance from scattering object to observation point. Superscript ″i″ denotes the incident field, and superscript ″s″ denotes the scattered field.

    (7)

    1.4Surrogate model

    Surrogate model is developed with experiment design methods and approximation models.

    The full factorial design (FFD) has advantages of analyzing interactions among factors and effects of each factor on the system.

    Radial basis functions were developed by Hardy[13]which use linear combinations of a symmetric function based on Euclidean distance to establish approximation models. Radial basis function (RBF) approximations fit good to arbitrary contours of both deterministic and stochastic response functions. A simple form of RBF is

    (8)

    The predictive model should satisfy the following interpolation conditions

    (9)

    Eq.(8) can be expressed as

    (10)

    1.5CFD/CEM coupling method

    Based upon CFD, FVTD and surrogate model, an integration design about aerodynamic/stealth of rotor airfoil is developed. Fig.2 shows the flow chart of integrated design based on CFD/CEM coupling strategy. The method consists of three modules: grid generation, solvers and integrated design.

    1.5.1Grid generation module

    Satisfying density and orthogonality of grid by adjusting the source term in the Poisson equations, the airfoil O-type body-fitted and orthogonal grids are generated. The nodes, area and vector of computational grid data are presented by conversion program.

    1.5.2Solver modules

    Based upon finite volume method and B-L turbulence model, N-S equations are chosen to solve the flowfield and aerodynamics characteristics.

    Based upon FVTD method, Maxwell′s equations are chosen to solve the electromagnetics field and RCS characteristics.

    1.5.3Integrated design module

    An optimization systemic methodology is developed from FFD and RBF. By choosing suitable objective function and constraint condition, an integration design about aerodynamic/stealth of airfoil is conducted. If optimized airfoil that satisfies high lift-to-drag ratio and low scattering characteristics, the method provides airfoil geometric parameters, if not, recalculate.

    Fig.2 Flow chart of integrated design based on CFD/CEM coupling strategy

    2 Results and Discussion

    2.1Test cases

    The aerodynamic case: NACA0012 airfoil at Ma=0.7 and Re=9×106. As shown in Fig.3, the calculated lift, pressure distributions and polar curve are in good agreements with the experimental data[14]. It has been demonstrated that the method is effective to simulate the aerodynamic characteristics of rotor airfoil.

    Fig.3 Comparisons of numerical and experimental results for aerodynamic characteristics of NACA0012 airfoil

    The RCS case: NACA0012 airfoil at TM and TE waves, L=10λ, incident angleφ=90°. As shown in Fig.4, the calculated results are in excellent agreements with the reference data[15]. It suggests that the method is effective in simulating the stealth characteristics of airfoil.

    Fig.4 Comparisons of numerical and results for RCS characteristics of NACA0012 airfoil

    2.2Aerodynamic and RCS responses of airfoil parameters

    The parameters of airfoil are maximum thickness, maximum camber and different maximum thickness and camber combinations. The calculated status:Ma=0.4,Re=9×106, angle of attackα=0°, TM wave, and incident angleφ=0°.

    2.2.1Response to maximum thickness

    Fig.5 shows aerodynamic and RCS characteristics of NACA airfoils with different maximum thicknesses. The lift coefficient of NACA24 Tmaxchanges relatively flat and the drag coefficient increases rapidly as shown in Fig.5(a), where Tmaxdenotes maximum thickness. The surface pressure coefficient distributions of the three airfoils are compared in Fig.5(b). The upper part distributions of Fig.5(c) depict RCS of five airfoils, and its lower part is the RCS difference of NACA2410 with the other airfoils. With the increase of the airfoil maximum thickness, the curvatures of leading and trailing edge become large, and the distributions of scattering energy are changed. As a result, the scattering fields of leading edge are more and more stronger,and RCS of airfoil trailing edge shows more obvious oscillation.

    Fig.5 Aerodynamic and RCS characteristics of NACA series airfoils with different maximum thicknesses

    2.2.2Response to maximum camber

    Fig.6 shows aerodynamic and RCS characteristics of NACA airfoils with different maximum cambers. The lift and drag coefficients of NACA Cmax412 increase rapidly shown in Fig.6(a), where Cmaxdenotes airfoil maximum camber. The surface pressure coefficient distributions of the three airfoils are shown in Fig.6(b). The upper part distributions of Fig.6(c) depict RCS of the five airfoils, and its lower part is the RCS difference of NACA1412 with the other airfoils. With the increase of the airfoil maximum camber, the curvatures of upside and downside surfaces become small, and the shape of trailing edge is changed significantly. As a result, the RCS amplitudes of upside surface are improved, the RCS amplitudes of downside surface are reduced, and RCS oscillations in other parts are not significant except at the trailing edge of airfoil.

    Fig.6 Aerodynamic and RCS characteristics of NACA series airfoils with different maximum cambers

    2.2.3Response to combinations of maximum thickness and camber

    Fig.7 shows aerodynamic and RCS characteristics of NACA series airfoils with different maximum thickness and camber combinations. For integration design, we hope K (the lift-to-drag ratio) is higher and RCS mean value is lower. As can be seen, the RCS distributions about leading edge, upside, downside and trailing edge of airfoils are different. The airfoil lift-to-drag ratio of upper part in Fig.7 is higher, which is beneficial to the aerodynamic characteristics, but not conducive to reducing RCS. The RCS mean value of lower part in Fig.7 is smaller, which are beneficial to the stealth characteristics, but not conducive to aerodynamic performances. So choosing theoptimal airfoil with high aerodynamic performance and low scattering characteristics is a compromised process.

    Fig.7 K and characteristics distribution of NACA series airfoils at four receiving azimuthal angles

    3 Integrated Design on Aerodynamic and Stealth of Airfoil

    3.1Integrated analyses

    The integrated analyses about aerodynamic and stealth characteristics of airfoil are an MDO issue, and the shapes of airfoil that can improve aerodynamic performance and reduce RCS at the same time are usually inconsistent, so the key is to find the aerodynamic/stealth compromised conditions which can be described as Pareto front efficiently and accurately. The multi-objective problem can be transformed into a single objective problem by the linear weighted sum method.

    NACA Cmax4Tmaxseries airfoils are selected for investigation. The samples about different thickness and camber combinations of NACA series airfoils are selected by FFD, then the aerodynamic/stealth characteristics of airfoils are calculated by CFD and FVTD methods respectively, and the fitting responses are obtained by the RBF. The total 25(5×5) samples (C=1—5,ΔC=1,T=10—18,ΔT=2) in design space, and the total 4 000 (50×80) fitting samples (C=1—5,ΔC=0.1,T=10—18,ΔT=0.1) in design space.

    Fig.8 shows K and RCS distributions of NACA airfoil with different maximum thickness and camber combinations (ψ=180°±30°). As can be seen, a Pareto front denoting the increase of lift-to-drag ratio and decrease of the mean RCS has been calculated in Fig.8(b). The fitting 2D perspective projecting drawing about K and RCS distributions of different NACA airfoils are shown in Fig.8(c) and Fig.8(d), respectively. As a result, designers can choose the Pareto front or objective function with suitable constraints to find the optimized airfoil that satisfies the aerodynamic/stealth requirements at the same time in the fitting curved surface.

    Fig.8 K and RCS characteristics of NACA series airfoils with different maximum thickness and camber combinations (ψ=180°±30°)

    Fig.9 shows RCS characteristics about four receiving azimuthal regions (leading edge, upside, downside and trailing edge) of NACA Cmax4Tmaxseries airfoils with different maximum thickness and camber combinations. As can be seen, four receiving azimuthal regions of NACA airfoils have different Pareto fronts, and every one of regions has its corresponding K/RCS Pareto front. So the RCS responses about four important scattering regions are all important for a rotating blade due to its special motion style.

    3.2Integrated design

    Based on influence factors about aerodynamic performance and four scattering regions of rotor airfoil, the optimized airfoil can be designed by appropriate objective function and constraint condition.

    Design status: Ma=0.4, Re=9×106, angle of attack α=0°, TM wave incident angelφ=0°, L=10λ.

    The lift-to-drag ratio and RCS mean value about leading edge (L), upside (U), downside (D), trailing edge (T) of airfoil are normalized:

    (11)

    Objective function

    (12)

    (13)

    Table 1shows the comparisons of weighted sum between baseline and optimized airfoil.The aerodynamic characteristics of NACA 5410 airfoil are the best,but RCS weighted sum at the four regions is not the minimum.The stealthy characteristics of NACA 1410 airfoil are the best,but aerodynamic performances(lift -to-drag ratio)are not optimum.When the maximum thickness is and the maximum camber is 4.3%,the combined airfoil satisfies the objective function and constraint condition.The weighted sum error between calculated and fitting sample from surro-gate model is small.As a result,it is demonstrated that the optimal method can satisfy the requirements of practical applications.

    Fig.9 RCS characteristics of NACA airfoils with different maximum thickness and camber combinations

    Table 1 Comparisons of weighted sum between baseline and optimized airfoil

    Fig.10 shows the comparisons of aerodynamic and RCS characteristics between baseline and optimized airfoil. Although the optimized airfoil is not the optimum aerodynamic solution, its aerodynamic and stealth comprehensive performances are the best. Comparing with the RCS amplitudes of NACA1410 and NACA5410 airfoils (especially trailing edge 320°≤ψ≤340°), the RCS amplitudes of the optimized airfoil decrease significantly. At the same time, comparing with aerodynamic performances of NACA1410, the pressure distributions and the lift-to-drag ratio of the optimized airfoil are improved obviously.

    Fig.10 Comparisons of aerodynamic and RCS characteristics between baseline and optimized airfoils

    4 Conclusions

    An integrated optimization design method about aerodynamic/stealth is developed for rotor airfoils, and the optimized airfoil can be designed by this method. From the results presented in this paper, the following conclusions can be drawn:

    (1) The high precision numerical method utilizing the N-S and Maxwell′s equations can effectively simulate the characteristics about aerodynamic/stealth of rotor airfoils.

    (2) Based upon surrogate model optimal techniques, an integration design of rotor airfoil about CFD/CEM coupling method is established, and it can be used to accurately and efficiently design the rotor airfoil with aerodynamic performance improvement and RCS reduction.

    (3) The aerodynamic performances are significantly influenced by the maximum camber of airfoil, and the stealth characteristics are greatly influenced by maximum thickness of airfoil. The selection of rotor airfoil with high lift-to-drag ratio and low scattering characteristics is a process of seeking compromised requirements, and the optimal airfoil can be found through comprehensive analyses.

    [1]STRAWN R C, CARADONNA F X, DUQUE E P N. 30 years rotorcraft computational fluid dynamics research and development[J]. Journal of the American Helicopter Society, 2006, 51(1): 5-21.

    [2]SHANKAR V, HILL W, MOHAMMADIAN A H. A CFD-based finite-volume procedure for computational electromagnetic interdisciplinary applications of CFD methods:A1AA89-1987-CP[R]. 1989.

    [3]CAMBEROS J A. COBRA-A FVTD code for electromagnetic scattering over complex shapes[R]. AIAA 02-1093, 2002.

    [4]DEORE N, CHATTERJEE A. A cell-vertex finite volume time domain method for electromagnetic scattering[J]. Progress in Electromagnetics Research, 2010, 12:1-15.

    [5]FUMEAUX C, KARAN K, VAHLDIECK R. Spherical perfectly matched absorber for finite volume 3D domain truncation[J]. IEEE Trans Microwave Theory Tech,2007, 55(12):2773-2781.

    [6]HOANG V, DAM C P, HARRY A D. Airfoil shaping for reduced radar cross section[J]. Journal of Aircraft, 1994, 31(4):787-793.

    [7]ZHU Z Q, FU H Y, YU R X, et al. Study on multi-objective optimization design of airfoil and wing[J]. Science in China (Series E), 2003, 33(11):999-1006. (in Chinese)

    [8]ZHAO Q J, XU G H, ZHAO J G. Numerical simulations of the unsteady flowfield of helicopter rotors on moving embedded grid[J]. Aerospace Science and Technology, 2005, 9(2): 117-124.

    [9]ZHAO Q J, XU G H, ZHAO J G. New hybrid method for predicting the flowfields of helicopter rotors[J]. Journal of Aircraft, 2006, 43(2):72-380.

    [10]STOLCIS L, JOHNSTON L J. Solution of the Euler equations on unstructured grids for two-dimensional compressible flow[J]. Aeronautical Journal, 1990, 94(936):181-195.

    [11]JOSEPH L S, WARMING R F. Flux vector splitting of the inviscid gasdynamic equations with application to finite-difference methods[J]. Journal of Computational Physics, 1981, 40(2):263-293.

    [12]SHANG J S, GAITONDE D. Scattered electromagnetic field of a reentry vehicle[R]. AIAA 94-0231, 1994.

    [13]HARDY R L. Multiquadric equations of topography and other irregular surfaces[J]. Journal of Geophysical Research, 1971, 76(8):1905-1915.

    [14]TERRY L H. Viscous transonic airfoil workshop compendium of results: AIAA-87-1460[R]. 1987.

    [15]CHATTERJEE A, MYONG R S. Efficient implementation of higher-order finite volume time domain method for electrically large scatterers[J]. Progress In Electromagnetics Research, 2009, 17:233-255.

    Mr. Jiang Xiangwen is a Ph.D. student in aircraft design at Nanjing University of Aeronautics and Astronautics (NUAA), and his research interests are helicopter stealth design, helicopter CEM and helicopter CFD.

    Dr. Zhao Qijun is a professor and Ph.D. supervisor in the College of Aerospace Engineering at NUAA, where he received his Ph.D. degree in aircraft design. His main research interests are helicopter CFD, helicopter aerodynamics, aerodynamic shape design of rotor blades, helicopter stealth design, active flow control of rotors and rotor aeroacoustics.

    Mr. Zhao Guoqing is a Ph.D. student in aircraft design at NUAA, and his research interests are active flow control of rotor, helicopter CFD and helicopter aerodynamics.

    Mr. Meng Chen is a master student in aircraft design at NUAA, and his research interests are helicopter stealth design and helicopter CEM.

    (Executive Editor: Zhang Tong)

    , E-mail address: zhaoqijun@nuaa.edu.cn.

    How to cite this article: Jiang Xiangwen, Zhao Qijun, Zhao Guoqing, et al. Numerical optimization on aerodynamic/stealth characteristics of airfoil based on CFD/CEM coupling method[J]. Trans. Nanjing Univ. Aero. Astro., 2016,33(3):274-284.

    http://dx.doi.org/10.16356/j.1005-1120.2016.03.274

    V218Document code:AArticle ID:1005-1120(2016)03-0274-11

    啦啦啦观看免费观看视频高清| 毛片女人毛片| av免费在线看不卡| 美女大奶头视频| 久久这里只有精品中国| 国产男人的电影天堂91| 国产一区二区在线观看日韩| 亚洲精品aⅴ在线观看| 午夜福利高清视频| 亚洲激情五月婷婷啪啪| 国产精品一区二区性色av| 国产黄片美女视频| 中文资源天堂在线| 国产色婷婷99| 国产精品野战在线观看| 欧美变态另类bdsm刘玥| 成人午夜高清在线视频| 在线观看一区二区三区| 久久99蜜桃精品久久| 村上凉子中文字幕在线| 美女大奶头视频| 日韩大片免费观看网站 | 爱豆传媒免费全集在线观看| 黑人高潮一二区| 色综合亚洲欧美另类图片| 免费不卡的大黄色大毛片视频在线观看 | 成人高潮视频无遮挡免费网站| 亚洲国产高清在线一区二区三| 亚洲电影在线观看av| 国产亚洲5aaaaa淫片| 国产av在哪里看| 99热网站在线观看| 久久精品夜夜夜夜夜久久蜜豆| 日韩精品青青久久久久久| 亚洲精品自拍成人| 久久精品91蜜桃| 国产精品一区二区三区四区免费观看| 在线观看66精品国产| 欧美区成人在线视频| 国产精品久久久久久久电影| 国产成人精品久久久久久| 纵有疾风起免费观看全集完整版 | 成人亚洲精品av一区二区| 黄色欧美视频在线观看| 国产激情偷乱视频一区二区| 大又大粗又爽又黄少妇毛片口| 秋霞伦理黄片| 黄色欧美视频在线观看| 欧美日本视频| 欧美变态另类bdsm刘玥| 欧美日韩国产亚洲二区| 亚洲精华国产精华液的使用体验| 精品国产一区二区三区久久久樱花 | 国产单亲对白刺激| 久久久欧美国产精品| 精品国产一区二区三区久久久樱花 | 欧美高清性xxxxhd video| 成人二区视频| 国产午夜精品一二区理论片| 亚洲三级黄色毛片| 熟妇人妻久久中文字幕3abv| 成人高潮视频无遮挡免费网站| 午夜福利在线观看免费完整高清在| 午夜福利网站1000一区二区三区| 欧美又色又爽又黄视频| 欧美日本亚洲视频在线播放| 日韩三级伦理在线观看| 国产精品日韩av在线免费观看| 搡老妇女老女人老熟妇| 超碰av人人做人人爽久久| 综合色av麻豆| 观看美女的网站| 亚洲av一区综合| 一级毛片久久久久久久久女| 久久午夜福利片| 久久久久性生活片| 久久精品熟女亚洲av麻豆精品 | 99国产精品一区二区蜜桃av| 亚洲国产精品成人综合色| 在线免费十八禁| 一级av片app| 直男gayav资源| 国产日韩欧美在线精品| 久久鲁丝午夜福利片| 少妇高潮的动态图| 亚洲精品aⅴ在线观看| 久久久成人免费电影| 免费大片18禁| 色播亚洲综合网| 综合色丁香网| 六月丁香七月| 一个人观看的视频www高清免费观看| 中文乱码字字幕精品一区二区三区 | 亚洲熟妇中文字幕五十中出| 国产精品日韩av在线免费观看| 欧美zozozo另类| 亚洲欧美一区二区三区国产| 亚洲欧美日韩高清专用| 成人av在线播放网站| av女优亚洲男人天堂| 国产一级毛片在线| 精品久久久久久成人av| 成人综合一区亚洲| 国产精品乱码一区二三区的特点| 三级经典国产精品| 日韩欧美 国产精品| 波多野结衣高清无吗| 欧美日韩一区二区视频在线观看视频在线 | 91精品一卡2卡3卡4卡| 国产精品人妻久久久久久| 小说图片视频综合网站| 欧美又色又爽又黄视频| 搡女人真爽免费视频火全软件| 中文字幕熟女人妻在线| 最近视频中文字幕2019在线8| 成人无遮挡网站| 女的被弄到高潮叫床怎么办| 亚洲欧美精品综合久久99| 国产 一区 欧美 日韩| 色尼玛亚洲综合影院| 国产伦一二天堂av在线观看| 亚洲国产高清在线一区二区三| 男的添女的下面高潮视频| 黄片wwwwww| 亚洲av免费在线观看| 搡老妇女老女人老熟妇| 亚洲精品影视一区二区三区av| 久久精品夜色国产| 十八禁国产超污无遮挡网站| 国产又色又爽无遮挡免| 黄色一级大片看看| 成人三级黄色视频| 成人国产麻豆网| 国产视频首页在线观看| 国产成人aa在线观看| av在线老鸭窝| 赤兔流量卡办理| 久久精品人妻少妇| 亚洲精品国产成人久久av| 久久精品国产亚洲网站| 别揉我奶头 嗯啊视频| 一级毛片aaaaaa免费看小| 精品国产露脸久久av麻豆 | 看免费成人av毛片| 亚洲第一区二区三区不卡| 人妻夜夜爽99麻豆av| 美女国产视频在线观看| 男女视频在线观看网站免费| 亚洲美女搞黄在线观看| 日韩,欧美,国产一区二区三区 | 一夜夜www| 精品欧美国产一区二区三| 久久人妻av系列| 亚洲av二区三区四区| 国产乱人视频| 最新中文字幕久久久久| 国产精品日韩av在线免费观看| 精品久久久久久久末码| 中文字幕人妻熟人妻熟丝袜美| 麻豆成人av视频| 亚洲精品aⅴ在线观看| 亚洲精品乱久久久久久| 日本av手机在线免费观看| av在线天堂中文字幕| 91久久精品国产一区二区成人| 成年免费大片在线观看| 国产人妻一区二区三区在| 久久精品久久久久久久性| 久久久久网色| 欧美极品一区二区三区四区| 国产午夜精品论理片| 精品一区二区三区人妻视频| 成人三级黄色视频| 色哟哟·www| 欧美xxxx黑人xx丫x性爽| 久久久久性生活片| 国产欧美日韩精品一区二区| 黄色配什么色好看| 我的老师免费观看完整版| 亚洲成人精品中文字幕电影| 国产精品国产三级国产av玫瑰| 激情 狠狠 欧美| 亚洲四区av| 麻豆乱淫一区二区| kizo精华| 国产成人91sexporn| 国产麻豆成人av免费视频| 免费看光身美女| 国产欧美另类精品又又久久亚洲欧美| 又爽又黄无遮挡网站| 黄色配什么色好看| 日本-黄色视频高清免费观看| 老女人水多毛片| 不卡视频在线观看欧美| 亚洲av日韩在线播放| 亚洲av.av天堂| 麻豆国产97在线/欧美| 超碰av人人做人人爽久久| 精品99又大又爽又粗少妇毛片| 国产免费男女视频| 男人舔奶头视频| 国产亚洲最大av| 亚洲国产色片| 国产在线一区二区三区精 | 精华霜和精华液先用哪个| 日韩高清综合在线| 国产精品99久久久久久久久| 国产亚洲午夜精品一区二区久久 | 99热这里只有是精品在线观看| 亚洲经典国产精华液单| 91久久精品国产一区二区三区| 成人性生交大片免费视频hd| 国产亚洲一区二区精品| 日本av手机在线免费观看| 一本一本综合久久| 久热久热在线精品观看| 中文字幕av成人在线电影| 岛国在线免费视频观看| 天堂av国产一区二区熟女人妻| 日韩精品有码人妻一区| 久久99热6这里只有精品| 全区人妻精品视频| 国产成人a∨麻豆精品| 欧美日韩国产亚洲二区| 黑人高潮一二区| 嘟嘟电影网在线观看| 国产免费福利视频在线观看| 久久午夜福利片| 91精品一卡2卡3卡4卡| 国产精品一及| 国产69精品久久久久777片| 最近中文字幕2019免费版| 狂野欧美激情性xxxx在线观看| av线在线观看网站| 哪个播放器可以免费观看大片| 日韩亚洲欧美综合| 国产伦一二天堂av在线观看| a级毛片免费高清观看在线播放| 内地一区二区视频在线| 深夜a级毛片| 女人十人毛片免费观看3o分钟| 高清毛片免费看| 国产精品美女特级片免费视频播放器| 亚洲成人久久爱视频| 99热这里只有是精品50| 男人舔奶头视频| av在线播放精品| 高清毛片免费看| 大话2 男鬼变身卡| 有码 亚洲区| 成人鲁丝片一二三区免费| 久久鲁丝午夜福利片| 最近最新中文字幕免费大全7| 成人av在线播放网站| 国内精品一区二区在线观看| 免费av毛片视频| 亚洲最大成人手机在线| 天堂网av新在线| 国产免费一级a男人的天堂| 亚洲av.av天堂| 日韩亚洲欧美综合| 久久久久久久亚洲中文字幕| 色噜噜av男人的天堂激情| 在线免费观看不下载黄p国产| 在线a可以看的网站| 在线观看美女被高潮喷水网站| 联通29元200g的流量卡| 爱豆传媒免费全集在线观看| 亚洲久久久久久中文字幕| 又粗又爽又猛毛片免费看| 国模一区二区三区四区视频| 女人久久www免费人成看片 | 欧美变态另类bdsm刘玥| 国产黄a三级三级三级人| 内地一区二区视频在线| 欧美日韩精品成人综合77777| 亚洲欧美中文字幕日韩二区| 国产老妇女一区| 一级毛片久久久久久久久女| 欧美日本视频| 少妇的逼好多水| 级片在线观看| 日韩中字成人| 婷婷色av中文字幕| 国产午夜福利久久久久久| 一区二区三区四区激情视频| 欧美+日韩+精品| 麻豆国产97在线/欧美| 国产大屁股一区二区在线视频| 精品人妻视频免费看| 一本一本综合久久| 精品熟女少妇av免费看| 一区二区三区免费毛片| 99久久九九国产精品国产免费| av在线天堂中文字幕| 久久精品熟女亚洲av麻豆精品 | 久久精品综合一区二区三区| 亚洲丝袜综合中文字幕| 日韩欧美三级三区| 九九爱精品视频在线观看| 深夜a级毛片| 少妇人妻精品综合一区二区| 日本免费一区二区三区高清不卡| 天天躁日日操中文字幕| 麻豆成人av视频| 久久久久久大精品| 精品国内亚洲2022精品成人| 国产精品久久久久久精品电影| 18禁动态无遮挡网站| 人人妻人人澡欧美一区二区| 99热这里只有是精品在线观看| 成人毛片a级毛片在线播放| 午夜福利在线观看吧| 亚洲国产精品合色在线| 一夜夜www| 中文资源天堂在线| 一级二级三级毛片免费看| 免费观看精品视频网站| av又黄又爽大尺度在线免费看 | 五月伊人婷婷丁香| 欧美成人精品欧美一级黄| 免费看a级黄色片| 亚洲欧美中文字幕日韩二区| 午夜福利高清视频| 狂野欧美白嫩少妇大欣赏| 日本黄大片高清| 亚洲国产最新在线播放| 一个人看的www免费观看视频| 嫩草影院新地址| 免费av观看视频| 丰满乱子伦码专区| 成人午夜精彩视频在线观看| 日本猛色少妇xxxxx猛交久久| 乱码一卡2卡4卡精品| 国产精品av视频在线免费观看| 晚上一个人看的免费电影| 午夜福利在线在线| 韩国高清视频一区二区三区| 亚洲真实伦在线观看| 三级毛片av免费| 亚洲精品aⅴ在线观看| 日本欧美国产在线视频| 日本-黄色视频高清免费观看| 午夜老司机福利剧场| 大香蕉久久网| 欧美zozozo另类| 日韩,欧美,国产一区二区三区 | 亚洲电影在线观看av| 最后的刺客免费高清国语| 国产精品.久久久| 两个人视频免费观看高清| 国产免费男女视频| 一区二区三区四区激情视频| 欧美不卡视频在线免费观看| 欧美zozozo另类| 人妻制服诱惑在线中文字幕| 卡戴珊不雅视频在线播放| 伊人久久精品亚洲午夜| 搡老妇女老女人老熟妇| 国产毛片a区久久久久| 视频中文字幕在线观看| 亚洲国产精品合色在线| av卡一久久| 网址你懂的国产日韩在线| 久久99热这里只频精品6学生 | 色哟哟·www| 久久精品熟女亚洲av麻豆精品 | 日本爱情动作片www.在线观看| 特级一级黄色大片| 搡老妇女老女人老熟妇| 欧美不卡视频在线免费观看| 97热精品久久久久久| 网址你懂的国产日韩在线| 毛片一级片免费看久久久久| 伦理电影大哥的女人| 91在线精品国自产拍蜜月| 18+在线观看网站| 婷婷六月久久综合丁香| 亚洲国产精品成人综合色| 色哟哟·www| 国产69精品久久久久777片| 在线观看66精品国产| 嫩草影院精品99| 亚洲国产日韩欧美精品在线观看| 校园人妻丝袜中文字幕| 白带黄色成豆腐渣| 午夜福利在线观看吧| 最近中文字幕2019免费版| 能在线免费看毛片的网站| 国产av码专区亚洲av| 国产精品久久久久久av不卡| 老司机影院毛片| 女人久久www免费人成看片 | 国产精品一区二区三区四区免费观看| 午夜福利在线观看吧| 人体艺术视频欧美日本| 2021少妇久久久久久久久久久| 日本黄色视频三级网站网址| 午夜爱爱视频在线播放| 亚洲精品乱码久久久久久按摩| 国产黄色视频一区二区在线观看 | 亚洲美女搞黄在线观看| 免费电影在线观看免费观看| 久久精品熟女亚洲av麻豆精品 | 91精品伊人久久大香线蕉| 夫妻性生交免费视频一级片| 国产精品嫩草影院av在线观看| 日韩欧美 国产精品| 三级毛片av免费| 亚洲精品,欧美精品| 99热全是精品| 国产不卡一卡二| 欧美高清性xxxxhd video| 亚洲最大成人av| 69人妻影院| 国产白丝娇喘喷水9色精品| 欧美成人a在线观看| 免费av不卡在线播放| 日本一二三区视频观看| 国产精品综合久久久久久久免费| 午夜激情欧美在线| 婷婷色综合大香蕉| 老师上课跳d突然被开到最大视频| 国产精品av视频在线免费观看| 中文字幕人妻熟人妻熟丝袜美| 亚洲国产欧美在线一区| 看片在线看免费视频| 久久久久久大精品| 少妇熟女aⅴ在线视频| 亚洲婷婷狠狠爱综合网| 天堂中文最新版在线下载 | 国国产精品蜜臀av免费| 久久亚洲国产成人精品v| 嫩草影院新地址| 人人妻人人澡人人爽人人夜夜 | 三级国产精品片| 亚洲精品成人久久久久久| 久久久久久久久久久丰满| 我的女老师完整版在线观看| 亚洲人成网站在线播| 欧美日韩在线观看h| 少妇人妻精品综合一区二区| 成人毛片a级毛片在线播放| 18禁裸乳无遮挡免费网站照片| 精品少妇黑人巨大在线播放 | 亚洲欧美成人精品一区二区| 久久久久久久午夜电影| 国产免费又黄又爽又色| 日韩三级伦理在线观看| 丝袜喷水一区| 最近最新中文字幕免费大全7| 成年av动漫网址| 只有这里有精品99| 99热6这里只有精品| 国产免费福利视频在线观看| 国产精华一区二区三区| av.在线天堂| 久久99热这里只频精品6学生 | 日本色播在线视频| 国产精品国产三级国产专区5o | 久99久视频精品免费| 99视频精品全部免费 在线| 欧美激情在线99| 久久亚洲国产成人精品v| 久久精品综合一区二区三区| 成人欧美大片| 高清av免费在线| 老女人水多毛片| 久久久成人免费电影| 精品久久久噜噜| 我要看日韩黄色一级片| 国语自产精品视频在线第100页| 久久国内精品自在自线图片| 日本五十路高清| 国产精品蜜桃在线观看| 国产欧美另类精品又又久久亚洲欧美| 亚洲成av人片在线播放无| 女人十人毛片免费观看3o分钟| 全区人妻精品视频| 韩国av在线不卡| 免费观看a级毛片全部| 久久久久久久久久久丰满| 国产av不卡久久| 麻豆成人av视频| av国产久精品久网站免费入址| 国产成人精品久久久久久| 久久精品国产亚洲网站| 亚洲av成人精品一二三区| 欧美97在线视频| 成年女人永久免费观看视频| 亚洲国产精品合色在线| 男人和女人高潮做爰伦理| 亚洲av中文av极速乱| 欧美极品一区二区三区四区| 亚洲av成人av| 亚洲性久久影院| 一边摸一边抽搐一进一小说| 日韩av在线免费看完整版不卡| 中文字幕亚洲精品专区| 国产欧美另类精品又又久久亚洲欧美| 尾随美女入室| 国产精品久久视频播放| 91午夜精品亚洲一区二区三区| 老司机福利观看| 亚洲国产欧洲综合997久久,| 亚洲在久久综合| 亚洲欧美清纯卡通| 亚洲精品亚洲一区二区| 日本三级黄在线观看| 国产一区二区在线av高清观看| 国产成人freesex在线| 日韩高清综合在线| 日本五十路高清| 99久久成人亚洲精品观看| 久久久久久久午夜电影| 网址你懂的国产日韩在线| 亚洲欧美中文字幕日韩二区| 3wmmmm亚洲av在线观看| 联通29元200g的流量卡| 国产高清有码在线观看视频| 成人毛片60女人毛片免费| 日本黄色片子视频| 国产精品国产三级国产av玫瑰| 亚洲欧美成人精品一区二区| 亚洲国产最新在线播放| 蜜臀久久99精品久久宅男| 精品久久久久久久久久久久久| 变态另类丝袜制服| 亚洲欧美日韩东京热| 午夜福利视频1000在线观看| 男人舔奶头视频| 极品教师在线视频| 国产一区二区在线观看日韩| 中文字幕免费在线视频6| 日韩中字成人| 99久国产av精品| 亚洲自拍偷在线| 成人亚洲精品av一区二区| 国产真实伦视频高清在线观看| 99热6这里只有精品| 日日啪夜夜撸| 国产成人aa在线观看| 午夜日本视频在线| 国产视频内射| 亚洲乱码一区二区免费版| 国产视频内射| 97人妻精品一区二区三区麻豆| 女的被弄到高潮叫床怎么办| 精品国产三级普通话版| 又爽又黄a免费视频| 全区人妻精品视频| 老司机影院成人| 中文字幕av成人在线电影| 国产乱来视频区| av免费观看日本| 中文字幕制服av| 国产成人免费观看mmmm| 丝袜喷水一区| 国产黄a三级三级三级人| 亚洲成av人片在线播放无| 亚洲av一区综合| 欧美激情久久久久久爽电影| 综合色丁香网| 日本-黄色视频高清免费观看| 国产精品伦人一区二区| 国产高清视频在线观看网站| 人妻制服诱惑在线中文字幕| 水蜜桃什么品种好| 亚洲国产精品专区欧美| 日韩欧美在线乱码| 亚洲国产最新在线播放| 亚洲成人精品中文字幕电影| 啦啦啦观看免费观看视频高清| 欧美zozozo另类| 亚洲精品亚洲一区二区| 国产又黄又爽又无遮挡在线| 日本av手机在线免费观看| 国产高潮美女av| 亚洲图色成人| 偷拍熟女少妇极品色| 日本免费在线观看一区| 国产精品久久久久久久久免| 99久久中文字幕三级久久日本| 熟妇人妻久久中文字幕3abv| 久久久国产成人免费| 亚洲av成人精品一二三区| 在线播放无遮挡| 国产精品熟女久久久久浪| 男女下面进入的视频免费午夜| 久久久久久久久中文| 亚洲欧美清纯卡通| 日韩中字成人| 国产又色又爽无遮挡免| 国产亚洲av嫩草精品影院| 国产一区二区在线观看日韩| 少妇的逼水好多| 男插女下体视频免费在线播放| 97人妻精品一区二区三区麻豆| 秋霞伦理黄片| 日韩高清综合在线| 97人妻精品一区二区三区麻豆| 99久久精品一区二区三区| 日韩高清综合在线| 日本午夜av视频| 国产午夜精品一二区理论片| 禁无遮挡网站| 欧美日韩在线观看h| 国产精品野战在线观看| 18禁裸乳无遮挡免费网站照片| av免费观看日本| 人人妻人人看人人澡| 日本欧美国产在线视频| 搡女人真爽免费视频火全软件| av在线亚洲专区| 好男人在线观看高清免费视频|