• <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 ?

    Application of Propagation Characteristics of Translating-Pulsating Source Green Function in the Side-Wall Effects Discrimination

    2018-03-28 12:30:18XIAOWenbin
    船舶力學 2018年3期

    XIAO Wen-bin

    (Academy of Ocean Science and Technology,National University of Defense Technology,Changsha 410073,China)

    0 Introduction

    In the tank with finite breadth,side-wall effects may exert great influence on the ship model advancing in waves,which is mainly due to the reflection waves acting on the model.The waves produced by the model propagate toward the side wall of the tank,and then may go back to it.If there are side-wall effects,many experimental results,such as the motion response,wave excited force,unsteady wave pattern,fluctuating pressure,may be affected.Studies about these effects will contribute to the investigation of hydrodynamic performance difference in the open water and tank condition,and qualitative and quantitative analyses are expected for the side-wall effects in seakeeping model test[1].

    For the side-wall effects problem in waves,earlier researches focused on the model test of single ship[2-3].In 1978,15th ITTC proposed standards of seakeeping tests for a single floating body[4].Recently,Ghent University in Belgium and other institutes carried out the model tests of two ships in waves[5-8],but the side-wall effects were still not investigated in depth.In the model tests for two ships advancing parallel in waves,the transversal space in between needs to be adjustable in line with the different experimental conditions.However,the enlargement of transversal space may intensify the side-wall effects,which makes the test more difficult in test design and data analysis.The side-wall effects seem to be more complicated for two advancing models than a single one;the critical wavelength corresponding to each model needs to be considered,besides that,the radiation and diffraction waves generated by a model may act upon the other one.Therefore,the relative position of two models in the tank should be taken into consideration to explore the side-wall effects in regular waves.

    In the present paper,the phase function is extracted from the integral representation about 3-D translating-pulsating source Green function in frequency domain,and the stationary phase method is applied to decompose the near-field flow and wave components of the source.Constant phase curves and propagation wave patterns in the far field are then obtained.Based on the propagation characteristics of Bessho form Green function,a simple and practical method is proposed to discriminate the side-wall effects for two ship models advancing in close proximity.Under the experimental conditions,the side-wall effects are examined in a two-model test.

    1 Propagation characteristics of Bessho form Green function

    1.1 Integral representation

    A right-handed equilibrium axis system oxyz is defined in the condition of deep water with the origin o on the plane of undisturbed free surface,and the z-axis is positive upwards.Assuming that the 3-D translating-pulsating source is advancing at a uniform speed U and oscillating at a frequencyis the source point and(x,y, )z is the field point,and then the Bessho form Green function[9]can be written as follows:

    The generalized wave numbers here are represented by k1and k2,and sign is the symbolic function.In terms of the value of τ,the integral path of formula(1)can be divided into two kinds according to the Cauchy integral theorem,which is illustrated in Fig.1.

    Fig.1 Integral path of equation(1)in θ space

    By performing M=sgn c·m=sgn c·k1cosθ,the terms about k1in formula(1)can be transformed into formula(2)with a single integral form[10].

    1.2 Decomposition of near-field flow and wave components

    It is known from formula(2),can reflect some nature of exponent part of the exponential function,whose real component represents the oscillation amplitude and imaginary one the phase information.Therefore,the phase function about Bessho form Green function can be defined as

    According to the traits of phase function,the wave patterns in far field can be determined by the stationary phase analysis method[11-12].If dψ/dM=0,it is easy to obtain that

    By substituting formula(4b)into formula(3),the parametric equation of constant phase curve can then be presented as follows:

    The variation range of θ in formula(6)is linked with the integral path in Fig.1.In m plane,the integral path of the new integrand is transformed,which is illustrated in Fig.2 and Fig.3.

    Fig.2 The new integral path for terms about k1 in m space

    Fig.3 The new integral path for terms about k2 in m space

    The imaginary part of variable m is not equal to zero in the intervals identified by dashed lines in Fig.2 and Fig.3.X and Y are,by definition,real numbers,so there is no stationary phase in the corresponding intervals,which means the near-field flow component of the Bessho form Green function is described here.The solid-line intervals in Fig.2 and Fig.3 are divided into three parts including AA,D1and D2,whose contribution is dominant in far field.Therefore,the propagating waves can be determined by equation(5)in the three intervals above.

    1.3 Wave patterns in far field

    In the water with an infinite free-surface extent,the unsteady waves generated by a translating-pulsating source are closely related to the Strouhal number τ=Uωe/g and its patterns can be indicated by the constant phase curves which represent the wave crests or hollow at a specific time instant[13].Fig.4 shows the propagating wave patterns when the source is located below the origin o.Here X and Y are dimensionless parameters,which can signify the horizontal position between the field point and the source point.

    If 4τ<1,there are three distinct wave patterns including outer V wave from AA,inner V wave from D1and ring wave from D2.For the value of 4τ>1,D1and D2are corresponding to inner V wave and ring-fan wave respectively and AA to fan wave.The ring and ring-fan waves above can be considered as the modified ring waves due to the forward speed,and other wave patterns as the modified Kelvin wake due to the harmonic oscillation of the source.All the wave patterns are restricted in the wedge-shaped region which is symmetrical about the advancing course.For the pulsating source,its constant phase curves are circles with the same center and wavelength in all directions[12].By analyzing the wave patterns,the translating-pulsating source seems to be more truly to reflect the propagating waves generated by an advancing ship than the pulsating source dose,which is largely due to the fact that the former source posses special features of forward movement and harmonic oscillation simultaneously.

    Fig.4 Constant phase curves of wave patterns when the source is located below o(a)4τ<1;(b)4τ>1

    Fig.5 Cusp angle of ring-fan wave pattern

    Fig.6 Cusp angle of ring-fan wave pattern versus τ

    For the propagating region of the ring wave is the whole free surface area,it is impossible to neglect the side-wall effect when 4τ<1.It is worth noting that the propagating scope of the inner V and fan waves is always within the region of ring-fan wave pattern if 4τ>1.Consequently,the influence area of ring-fan wave can be regarded as the propagating region of the radiation and diffraction waves generated by the translating-pulsating source in the condition of 4τ>1.As shown in Fig.5,a cusp angle θris introduced,which is an angle between the boundary of ring-fan wave and the source course.Fig.6 depicts how this cusp angle changes in dependence of Strouhal number[13].As shown in this figure,the backward spreading feature of ring-fan wave is more and more significant as the advancing speed increases or oscillating frequency decreases,which is consistent with the observed result in physics.In addition,ringfan wave is still possible to emerge ahead of the source when 4τ>1.However,θris always less than 90 degrees if τ>0.272,side-wall effects in which condition is the focus of the present work.

    2 Discrimination of side-wall effect for single ship model

    In the seakeeping test for single ship,the model is generally set to the central axis of the tank.Fig.7 shows the ship waves reflect from the side walls at different cusp angle θr.Given the tank breadth BTand model length L,it can be easily concluded that there must be a geometric critical cusp angle θtto discriminate the side-wall effect.

    Fig.7 Waves generated by single model and reflected from the side walls of the tank

    If θris is larger than θt,the waves generated from the ship stem will act on the flow field at the ship stern nearby after side-wall reflection,and the tank wall interference will occur.If θr<θt,the side-wall effect is absent then.Based on the analysis above,a discrimination method of side-wall effect can be proposed for single ship model.The concrete steps are presented as follows.Firstly,the critical angle θtis solved by tank breadth BTand model length L as formula(7).In terms of the monotone function of cusp angle θrin dependence of τ,the Strouhal number is determined when θtequals to θrin the second step.Thirdly,the corresponding frequency ωeat a certain speed U can be obtained by the definition of τ=Uωe/g.And finally,the critical wavelength λtis achieved with parameters of wave frequency and wavelength.Through comparing the value of experimental wavelength with λt,the side-wall effect can then be identified.The flow diagram of the discrimination method above is illustrated in Fig.8,in which β is the wave-to-course angle with the value of zero in head waves.Input of this method is BT,L,U and propagating property of ring-fan waves.

    Fig.8 Flow diagram of discrimination about the side wall effect for single ship model

    Based on the tank breadth,model length,speed Froude number and wave circular frequency,15th ITTC recommended a standard for seakeeping experiment of single model in the form of check list[4],whose data essentially indicates the variation laws of the circular Strouhal number τ0=Uω0/g with the ratio BT/L.The relationship between τ0and τ is given in formula(8).

    Fig.9(a)and(b)illustrates the discrimination margin of side-wall effect for single model,in which the present results are shown with solid lines.Whichever to adopt to discriminate the effect,τ0or τ,the side-wall effect is not ignorable in the lower left region of the lines and vice versa.In addition,the discrimination data of 15th ITTC is listed in Fig.9(a).By comparison,present results calculated by τ0agree well with the standard data.Therefore,the discrimination method above proves to be correct and effective for single model.It is expected to apply this method to the seakeeping test of two ship models.

    Fig.9 Discrimination margin of side wall effect for single ship model

    3 Discrimination of side-wall effects for two ship models

    In the test of two models advancing in close proximity,the best layout plan is that the two models are arranged symmetrically around the central axis of tank.However,it may strengthen the reforming of towing system for there is only one towing device in universal tank.A simple solution is that one model labeled as ship a is arranged into the carriage navigation system,which is usually located in the central axis of tank.Without loss of generality,another model,labeled as ship b,is set on the starboard side of ship a.The transversal and longitudinal spaces between two models are set as Dyand Dx,respectively,as shown as in Fig.10.If Dy>0,ship b is on the starboard side of ship a.For Dx>0,ship b is ahead of ship a.

    Fig.10 Waves generated by two models and reflected from the side walls of tank

    The radiation and diffraction waves here are so complex that they need to be analyzed one by one.Taking Fig.10 as an example,the waves generated by the model may reflect back to interfere its own response in waves.In this case,the critical angle can be referenced by the single model.For ship a,this angle θtaais satisfied with formula(9a).For ship b,transversal space Dyis taken into account in the angle θtbbdue to its proximity to the right side wall,which is shown in formula(9b).

    where Laand Lbare the lengths of ship a and ship b,respectively.

    In addition,the waves from a model may act on the other one after the side-wall reflection.Because of the shadowing effect of ship hull,the interference waves between models’broad sides are restricted in a narrow area,which is an important feature of hydrodynamic interference when two ships are advancing parallel in close proximity.If the two models are not captured,this shadowing effect is not complete in waves[15].And there are radiation and diffraction waves produced by ship a on the starboard of ship b.Here the wave propagation must follow the shortest distance principle from one model to the other.For instance,the wave from ship a is quicker to reach ship b by the right side wall than the left side.So the critical angle θtbais determined by the right side wall as formula(9c).In a similar way,the angle θtabis given in formula(9d).

    Above all,the side-wall effects for two models advancing parallel in waves can be discriminated in terms of the four angles as formula(9a)~(9d).And the minimum value of them is defined as θtto determine if the side-wall effects occur.

    4 Instance analyses

    For the models test of Cheng Kung University in Ref.[16],the discrimination method above is applied to check the side-wall effects.Tab.1 shows the main particulars of the tested models.

    Tab.1 Main particulars of tested models

    In the test,two models are advancing in head regular waves with the wavelength range 1.93-6.24 m.The principal dimension of the towing tank is 180 m×8 m×3.5 m and speed Froude numbers Fnare 0,0.076 and 0.141.In the experimental condition with Dx=0,two kinds of model layout are discussed here.The first layout is that ship a is set in the central axis of tank and ship b is on the starboard side of ship a with Dy=0.72 m,0.82 m and 0.92 m.No matter how the transversal space changes,two models are arranged symmetrically around the central axis of tank in the other layout.

    When Fnequals to 0 or 0.076,side-wall effects occur in both layouts.For Fn=0.141,the critical wavelength appears near 5 m.Fig.11 depicts the wavelength range free of side-wall effect in the experimental conditions.From this figure,the critical wavelength tends to be shorter along with the increase of transversal space.For the transversal space is relative small(Dx/BT=9.0%~11.5%),the change of critical wavelength in accordance with the transversal space is not significant on the whole.

    Fig.11 Wavelength range free of side-wall effect(Fn=0.141)

    In addition,the wavelength range free of side-wall effect is boarder in the second layout than that in the first one.The symmetrical layout plan,though is more advantageous to avoid the side-wall effect,may enlarge the experimental difficulty and increase the equipment-testing workload.In order to minimize the interference of side-wall effect,the time-history data to be analyzed should be properly intercepted and deep research should focus on its quantitative analysis,which may be the future course of this problem.

    5 Conclusions

    Based on the propagation characteristics of translating-pulsating source Green function,a practical approach is proposed to discriminate the side-wall effects for single ship model and two models in waves.The main contents and conclusions in present paper are included below:

    (1)For the single integral representation about 3-D translating-pulsating source Green function of Bessho form in frequency domain,the parametric equation of constant phase curve is obtained by stationary phase method.The integral intervals of near-field flow and wave components are made clear by the real number property of constant phase curve.If 4τ>1,the propagating area of inner V and fan waves is always within the region of ring-fan wave pattern.And the influence scope of radiation-diffraction waves of the source can be considered as the propagating area of ring-fan wave.

    (2)Ring wave and ring-fan wave pattern may emerge ahead of the translating-pulsating source for τ<0.272,and then side-wall effects seem to be not ignored.If τ>0.272,the cusp angle of the source is larger than 90 degrees,therefore it is needed to discriminate the sidewall effects by corresponding method or regulation.

    (3)By comparing the ring-fan wave’s cusp angle and geometric critical cusp angle of experimental tank,a discrimination method and its implementing process are presented in the side-wall effect problem for single ship model,and the discrimination margin is obtained by the Strouhal number.Further,a discrimination method of side-wall effects is proposed for two models advancing parallel in regular waves based on the model particulars,tank breadth and relative position of two models,in which the interference of reflection waves acting on both models are taken into account by the shortest distance principle of propagating waves.

    (4)The present discrimination method of side-wall effects is not only suitable for the single model and two models test,but also can be applied to the seakeeping test of multihull vehicle and multiple ships.The future work is to further investigate the propagation velocity of the wave patterns,because there is time interval for the propagation waves from the ship to the side wall.

    [1]Tasai F,Takaki M,Ohkusu M.Ship motions in restricted waters[J].Journal of the Japan Society of Naval Architects and Ocean Engineers,1978,56:33-45.

    [2]Hosoda R.Effects of side-wall interference of towing tank on the results of experiments in waves(1)[J].Journal of the Society of Naval Architects of Japan,1976,139:23-30.

    [3]Hosoda R.Effects of side-wall interference of towing tank on the results of experiments in waves(2)[J].Journal of the Society of Naval Architects of Japan,1978,143:52-60.

    [4]The Seakeeping Committee of ITTC.Report of the seakeeping committee[C]//Proceedings of the 15th International Towing Tank Conference.Netherlands,1978:55-114.

    [5]Vantorre M,Verzhbitskaya E,Laforce E.Model test based formulations of ship-ship interaction forces[J].Ship Technology Research,2002,49(3):1-9.

    [6]Evert L,Marc V,Guilaume D.Captive model testing for ship to ship operations[C]//Proceedings of International Conference on Marine Simulation and Ship Maneuverability.Panama,2009:1-10.

    [7]Greet V K,Marc V,Guilaume D.Advanced model testing techniques for ship behavior in shallow and confined water[C]//Proceedings of the 1st International Conference on Advanced Model Measurement Technology for the EU Maritime Industry.Nantes,France,2009:158-172.

    [8]Zhao W H,Yang J M,Hu Z Q,et al.Recent developments on the hydrodynamics of floating liquid natural gas(FLNG)[J].Ocean Engineering,2011,38:1555-1567.

    [9]Bessho M.On the fundamental singularity in the theory of ship motion in a seaway[J].Memoirs of the Defense Academy of Japan,1977,17(8):95-105.

    [10]Iwashita H,Ohkusu M.Hydrodynamic forces on a ship moving with forward speed in waves[J].Journal of the Society of Naval Architects of Japan,1989,166:87-109.

    [11]Noblesse F,Hendrix D.On the theory of potential flow about a ship advancing in waves[J].Journal of Ship Research,1992,36(1):17-29.

    [12]Xu Y,Dong W C,Xiao W B.Study on far field wave patterns and their characteristics of Havelock form Green function[J].China Ocean Engineering,2013,27(3):283-298.

    [13]Chen X B,Diebold L.Analytical expressions of unsteady wave patterns[C]//Proceedings of the 14th International Workshop on Water Waves and Floating Bodies.Port Huron,USA,25-28.

    [14]Faltinsen O M.Hydrodynamics of high-speed marine vehicles[M].Cambridge University Press,UK,2005:99-140.

    [15]Xu Y.Study on the mechanism of hydrodynamic interaction between multiple ships advancing in waves at close proximity[D].Wuhan:Naval University of Engineering,2012.

    [16]Yang W H.Experimental verification of the seakeeping performance for two ships advancing parallel in waves[D].Taiwan:National Cheng Kung University,2001.

    [17]Mctaggart K,Cumming D,Hsiung C C,et al.Seakeeping of two ships in close proximity[J].Ocean Engineering,2003,30:1051-1063.

    男女边吃奶边做爰视频| 国产白丝娇喘喷水9色精品| 国产精品 国内视频| 日韩不卡一区二区三区视频在线| 久久97久久精品| 熟女人妻精品中文字幕| 国产午夜精品一二区理论片| 这个男人来自地球电影免费观看 | 国产男女超爽视频在线观看| 国产成人91sexporn| 一区二区三区四区激情视频| 美女视频免费永久观看网站| 欧美激情 高清一区二区三区| 天天操日日干夜夜撸| 波多野结衣一区麻豆| 日韩三级伦理在线观看| 97在线视频观看| 色视频在线一区二区三区| 最近的中文字幕免费完整| 亚洲国产看品久久| 国产永久视频网站| 激情五月婷婷亚洲| 97人妻天天添夜夜摸| 国产一区有黄有色的免费视频| 国产免费现黄频在线看| 又大又黄又爽视频免费| 99九九在线精品视频| 国产爽快片一区二区三区| 国产一区二区三区综合在线观看 | 丝袜在线中文字幕| 九草在线视频观看| 日本vs欧美在线观看视频| 黄色毛片三级朝国网站| 十八禁高潮呻吟视频| 女人久久www免费人成看片| 午夜av观看不卡| 久久影院123| 在线免费观看不下载黄p国产| 日韩电影二区| 欧美精品人与动牲交sv欧美| 精品久久国产蜜桃| 亚洲欧美日韩另类电影网站| 午夜福利,免费看| 免费高清在线观看视频在线观看| 亚洲精品久久午夜乱码| 丝瓜视频免费看黄片| 女性生殖器流出的白浆| 日韩中字成人| videossex国产| 黑人巨大精品欧美一区二区蜜桃 | 国产老妇伦熟女老妇高清| 在线观看一区二区三区激情| 天天躁夜夜躁狠狠久久av| 亚洲欧洲日产国产| 99热全是精品| 看免费成人av毛片| 草草在线视频免费看| 久久97久久精品| 中文字幕制服av| 岛国毛片在线播放| 成人国产麻豆网| 99久久综合免费| 国产在线一区二区三区精| 日韩熟女老妇一区二区性免费视频| 日韩中字成人| 好男人视频免费观看在线| 狠狠精品人妻久久久久久综合| 亚洲国产日韩一区二区| 日韩伦理黄色片| 啦啦啦中文免费视频观看日本| 亚洲av综合色区一区| 久久久久久久久久成人| 午夜av观看不卡| 久久久久久久精品精品| av黄色大香蕉| 寂寞人妻少妇视频99o| 免费不卡的大黄色大毛片视频在线观看| 午夜91福利影院| 亚洲精品一区蜜桃| 狠狠婷婷综合久久久久久88av| 国产极品粉嫩免费观看在线| 自拍欧美九色日韩亚洲蝌蚪91| 国产综合精华液| 人妻系列 视频| a级片在线免费高清观看视频| 蜜臀久久99精品久久宅男| 搡老乐熟女国产| 丰满饥渴人妻一区二区三| 精品人妻熟女毛片av久久网站| 欧美日韩视频精品一区| 国产免费一区二区三区四区乱码| 高清在线视频一区二区三区| 欧美xxⅹ黑人| 日韩av免费高清视频| 丝袜脚勾引网站| 久久久精品免费免费高清| 午夜91福利影院| 内地一区二区视频在线| 亚洲av欧美aⅴ国产| 国产亚洲最大av| 亚洲人与动物交配视频| 久久亚洲国产成人精品v| 日本与韩国留学比较| 日韩成人av中文字幕在线观看| 香蕉精品网在线| 女性生殖器流出的白浆| 最近最新中文字幕免费大全7| 欧美国产精品va在线观看不卡| 巨乳人妻的诱惑在线观看| 亚洲精品aⅴ在线观看| 欧美少妇被猛烈插入视频| 少妇熟女欧美另类| 18禁国产床啪视频网站| 亚洲一码二码三码区别大吗| 一级片免费观看大全| 在线 av 中文字幕| 国产免费又黄又爽又色| 午夜福利乱码中文字幕| 成人免费观看视频高清| 男女边摸边吃奶| 久久精品久久久久久噜噜老黄| 亚洲国产日韩一区二区| 亚洲精品乱码久久久久久按摩| 国产国拍精品亚洲av在线观看| 免费观看性生交大片5| 亚洲国产色片| a级毛色黄片| 91成人精品电影| 中国美白少妇内射xxxbb| 熟女电影av网| 少妇人妻 视频| 青春草亚洲视频在线观看| 王馨瑶露胸无遮挡在线观看| 国产乱来视频区| 天天影视国产精品| 色94色欧美一区二区| 国产精品国产三级专区第一集| 五月玫瑰六月丁香| 国产免费一区二区三区四区乱码| 欧美日韩亚洲高清精品| 久久久精品免费免费高清| 亚洲人成77777在线视频| 菩萨蛮人人尽说江南好唐韦庄| 国产1区2区3区精品| 欧美日韩视频高清一区二区三区二| 欧美日韩成人在线一区二区| 99香蕉大伊视频| 亚洲综合色网址| 中文字幕最新亚洲高清| 久久精品国产综合久久久 | 色网站视频免费| 国产极品天堂在线| 国产成人精品久久久久久| 在线看a的网站| www.色视频.com| 日本爱情动作片www.在线观看| 欧美日韩av久久| 国产亚洲精品第一综合不卡 | 一二三四中文在线观看免费高清| 免费看av在线观看网站| 精品熟女少妇av免费看| 日韩成人av中文字幕在线观看| 久久精品国产鲁丝片午夜精品| 国产成人精品久久久久久| 久久影院123| 老熟女久久久| av播播在线观看一区| 毛片一级片免费看久久久久| 国产精品国产av在线观看| 久久久久精品久久久久真实原创| 久久精品夜色国产| 插逼视频在线观看| 国产高清国产精品国产三级| 日本91视频免费播放| 日韩av不卡免费在线播放| av在线播放精品| av在线老鸭窝| 婷婷色综合大香蕉| 97人妻天天添夜夜摸| 久久久久精品人妻al黑| 日本猛色少妇xxxxx猛交久久| 婷婷色av中文字幕| 午夜福利网站1000一区二区三区| 国产成人免费无遮挡视频| 精品国产一区二区三区四区第35| 国产精品成人在线| www日本在线高清视频| 熟女av电影| 99热网站在线观看| 欧美亚洲日本最大视频资源| 日韩人妻精品一区2区三区| 国精品久久久久久国模美| 国产免费又黄又爽又色| 国产麻豆69| 亚洲欧美中文字幕日韩二区| videosex国产| 久久午夜综合久久蜜桃| 日本欧美视频一区| 亚洲欧洲国产日韩| 性色av一级| 国产熟女欧美一区二区| 日日摸夜夜添夜夜爱| 男女无遮挡免费网站观看| 观看av在线不卡| 亚洲精品日本国产第一区| 精品人妻熟女毛片av久久网站| 黑人高潮一二区| 啦啦啦啦在线视频资源| 亚洲欧美一区二区三区黑人 | 免费看av在线观看网站| 日韩人妻精品一区2区三区| 男男h啪啪无遮挡| 在线观看免费视频网站a站| 少妇被粗大猛烈的视频| 在线 av 中文字幕| 九九在线视频观看精品| av国产精品久久久久影院| 夜夜爽夜夜爽视频| 少妇被粗大猛烈的视频| 丝袜脚勾引网站| 看十八女毛片水多多多| 两个人看的免费小视频| 久久精品熟女亚洲av麻豆精品| 99热国产这里只有精品6| 曰老女人黄片| 插逼视频在线观看| 国产成人a∨麻豆精品| 成人午夜精彩视频在线观看| 十分钟在线观看高清视频www| 三级国产精品片| 你懂的网址亚洲精品在线观看| 免费大片18禁| 国产成人精品久久久久久| 久久热在线av| 精品人妻在线不人妻| 亚洲国产av影院在线观看| 秋霞在线观看毛片| 男的添女的下面高潮视频| 91精品国产国语对白视频| 久久这里有精品视频免费| 极品人妻少妇av视频| 性色av一级| 亚洲一码二码三码区别大吗| 亚洲综合精品二区| 亚洲av电影在线进入| 欧美性感艳星| 国产又色又爽无遮挡免| 久久久国产一区二区| 久久久久久久大尺度免费视频| 纵有疾风起免费观看全集完整版| 国产精品久久久久久av不卡| 99国产精品免费福利视频| 大片电影免费在线观看免费| 精品亚洲成国产av| 成人国产麻豆网| 国产亚洲一区二区精品| 18在线观看网站| 日韩免费高清中文字幕av| 精品少妇黑人巨大在线播放| 中文字幕最新亚洲高清| 80岁老熟妇乱子伦牲交| 亚洲综合色惰| 亚洲精品中文字幕在线视频| 欧美精品人与动牲交sv欧美| 国产老妇伦熟女老妇高清| 亚洲经典国产精华液单| 亚洲av电影在线观看一区二区三区| 丁香六月天网| 一区在线观看完整版| 最近2019中文字幕mv第一页| 国产成人精品无人区| 18禁在线无遮挡免费观看视频| 熟女av电影| 亚洲内射少妇av| videos熟女内射| av免费观看日本| 侵犯人妻中文字幕一二三四区| 九九在线视频观看精品| videossex国产| 日本黄色日本黄色录像| 久久人人爽av亚洲精品天堂| 97超碰精品成人国产| 午夜激情久久久久久久| 国产成人精品一,二区| 精品国产乱码久久久久久小说| 免费黄色在线免费观看| av网站免费在线观看视频| 午夜老司机福利剧场| 国产探花极品一区二区| 久久午夜综合久久蜜桃| kizo精华| 中国国产av一级| 美女中出高潮动态图| 亚洲伊人久久精品综合| 久久久久久人妻| 亚洲美女黄色视频免费看| 国产成人aa在线观看| 成年美女黄网站色视频大全免费| 久久 成人 亚洲| 秋霞伦理黄片| 在线观看免费日韩欧美大片| 国产精品久久久久久av不卡| 国产淫语在线视频| 国产一区二区在线观看日韩| 最后的刺客免费高清国语| av在线老鸭窝| av在线观看视频网站免费| 精品一区二区三区视频在线| 午夜福利在线观看免费完整高清在| 国产免费视频播放在线视频| 亚洲中文av在线| 精品少妇久久久久久888优播| 日韩在线高清观看一区二区三区| 久久午夜综合久久蜜桃| 亚洲欧美成人精品一区二区| 日韩av免费高清视频| 亚洲欧美色中文字幕在线| 精品久久久久久电影网| 十八禁高潮呻吟视频| 国产极品粉嫩免费观看在线| 久久久久久人妻| 哪个播放器可以免费观看大片| 亚洲五月色婷婷综合| 国产成人精品无人区| 99久久精品国产国产毛片| 国产成人精品在线电影| 久久精品国产综合久久久 | 成年人午夜在线观看视频| 插逼视频在线观看| 2021少妇久久久久久久久久久| 国产精品一区二区在线观看99| 久久精品久久精品一区二区三区| 十八禁网站网址无遮挡| 国精品久久久久久国模美| 十八禁网站网址无遮挡| 最近中文字幕高清免费大全6| 免费看不卡的av| 九色成人免费人妻av| 国产又爽黄色视频| 亚洲av福利一区| 乱人伦中国视频| 搡女人真爽免费视频火全软件| 欧美 日韩 精品 国产| 欧美精品一区二区免费开放| 丰满饥渴人妻一区二区三| 久久久久久久久久久久大奶| 欧美精品亚洲一区二区| freevideosex欧美| 欧美丝袜亚洲另类| 国产精品一国产av| 国产成人欧美| 免费在线观看黄色视频的| 欧美日韩亚洲高清精品| 视频区图区小说| 久久久久久久国产电影| 精品一区二区三区四区五区乱码 | 国产 一区精品| 国产无遮挡羞羞视频在线观看| 国产精品国产三级专区第一集| 99热6这里只有精品| 1024视频免费在线观看| 少妇熟女欧美另类| 日本av免费视频播放| 99热这里只有是精品在线观看| 亚洲精品日韩在线中文字幕| 99热6这里只有精品| 亚洲精品视频女| 欧美精品亚洲一区二区| 这个男人来自地球电影免费观看 | av电影中文网址| 大陆偷拍与自拍| 91精品伊人久久大香线蕉| 成年人免费黄色播放视频| 视频中文字幕在线观看| 99国产精品免费福利视频| 色视频在线一区二区三区| 久久精品国产亚洲av涩爱| 亚洲精品久久午夜乱码| 久久久久久久久久久免费av| 一区二区三区乱码不卡18| 国产精品久久久久久久电影| av不卡在线播放| 亚洲欧美精品自产自拍| 欧美人与性动交α欧美软件 | 下体分泌物呈黄色| 2022亚洲国产成人精品| 黄网站色视频无遮挡免费观看| 汤姆久久久久久久影院中文字幕| 美国免费a级毛片| 亚洲性久久影院| 在线观看美女被高潮喷水网站| 亚洲丝袜综合中文字幕| 日韩大片免费观看网站| 精品亚洲成国产av| 免费不卡的大黄色大毛片视频在线观看| 久久久国产欧美日韩av| 2018国产大陆天天弄谢| 欧美老熟妇乱子伦牲交| 亚洲,一卡二卡三卡| 岛国毛片在线播放| 美国免费a级毛片| 成年美女黄网站色视频大全免费| a级毛片黄视频| 日韩一本色道免费dvd| 99热全是精品| av福利片在线| 在线观看人妻少妇| 国产激情久久老熟女| 国产精品国产av在线观看| 久久热在线av| 成人免费观看视频高清| 国产精品久久久久成人av| 欧美xxⅹ黑人| 99热6这里只有精品| 两性夫妻黄色片 | 久久久久久久久久成人| av卡一久久| 国产精品久久久久久久电影| 国产精品99久久99久久久不卡 | 成人毛片60女人毛片免费| 最近2019中文字幕mv第一页| 免费高清在线观看视频在线观看| 久久久久久人人人人人| 国产成人91sexporn| 亚洲第一av免费看| 久久久精品94久久精品| 久久精品国产亚洲av涩爱| 91精品国产国语对白视频| 最近中文字幕2019免费版| av不卡在线播放| 日韩av不卡免费在线播放| 国产亚洲一区二区精品| 少妇人妻 视频| 久久精品国产a三级三级三级| 亚洲成国产人片在线观看| 巨乳人妻的诱惑在线观看| 一级毛片电影观看| 在线天堂中文资源库| av国产久精品久网站免费入址| 永久网站在线| a级毛色黄片| 看非洲黑人一级黄片| av在线app专区| 亚洲av福利一区| 免费看不卡的av| av国产精品久久久久影院| 免费高清在线观看日韩| 国产精品久久久久久精品电影小说| 日韩av不卡免费在线播放| 在线观看www视频免费| 99香蕉大伊视频| videos熟女内射| 精品午夜福利在线看| 日韩一区二区视频免费看| 成人18禁高潮啪啪吃奶动态图| 九草在线视频观看| av不卡在线播放| 亚洲av中文av极速乱| 女的被弄到高潮叫床怎么办| 久久久久视频综合| 国产又色又爽无遮挡免| 久久韩国三级中文字幕| 国产成人精品久久久久久| 日本色播在线视频| 国产亚洲精品第一综合不卡 | 欧美激情极品国产一区二区三区 | 亚洲一区二区三区欧美精品| 中文字幕制服av| 一本色道久久久久久精品综合| 日韩欧美一区视频在线观看| 在线观看美女被高潮喷水网站| 国产精品一区二区在线观看99| 亚洲第一区二区三区不卡| 久久国产亚洲av麻豆专区| 尾随美女入室| 成人18禁高潮啪啪吃奶动态图| 秋霞伦理黄片| 各种免费的搞黄视频| 国产一区有黄有色的免费视频| 有码 亚洲区| 亚洲性久久影院| 精品国产国语对白av| 亚洲av日韩在线播放| 久久99热6这里只有精品| 草草在线视频免费看| 亚洲三级黄色毛片| 人人妻人人添人人爽欧美一区卜| 免费高清在线观看日韩| 9热在线视频观看99| 大香蕉久久成人网| 新久久久久国产一级毛片| 国产精品免费大片| 国产一区二区三区综合在线观看 | 交换朋友夫妻互换小说| 飞空精品影院首页| 美女主播在线视频| 国产一级毛片在线| 男人操女人黄网站| 欧美xxxx性猛交bbbb| 纵有疾风起免费观看全集完整版| 一本大道久久a久久精品| 精品国产一区二区三区久久久樱花| 午夜免费鲁丝| 午夜免费男女啪啪视频观看| 又粗又硬又长又爽又黄的视频| 日韩视频在线欧美| 啦啦啦在线观看免费高清www| 亚洲第一av免费看| 又粗又硬又长又爽又黄的视频| 免费黄频网站在线观看国产| 免费不卡的大黄色大毛片视频在线观看| tube8黄色片| 成人国语在线视频| 欧美精品高潮呻吟av久久| 亚洲综合色惰| av在线app专区| 亚洲av.av天堂| 老女人水多毛片| 亚洲综合色惰| 极品少妇高潮喷水抽搐| 国产成人91sexporn| 丁香六月天网| 又粗又硬又长又爽又黄的视频| 日韩精品免费视频一区二区三区 | a级毛片黄视频| 九九爱精品视频在线观看| 国产免费现黄频在线看| 午夜福利视频精品| 国产在线视频一区二区| 黑人欧美特级aaaaaa片| 国产午夜精品一二区理论片| 一边亲一边摸免费视频| 赤兔流量卡办理| 色视频在线一区二区三区| www.av在线官网国产| 最近中文字幕高清免费大全6| 黄色配什么色好看| 热re99久久国产66热| 成人亚洲欧美一区二区av| 亚洲综合精品二区| 永久网站在线| 黄色视频在线播放观看不卡| 亚洲激情五月婷婷啪啪| 三级国产精品片| 亚洲色图 男人天堂 中文字幕 | 久久久久久久亚洲中文字幕| 国产亚洲欧美精品永久| av视频免费观看在线观看| 在线观看国产h片| 久久精品国产亚洲av涩爱| 91精品国产国语对白视频| 99国产综合亚洲精品| 久久国内精品自在自线图片| 边亲边吃奶的免费视频| 久久精品夜色国产| 两性夫妻黄色片 | 99视频精品全部免费 在线| 又黄又粗又硬又大视频| 交换朋友夫妻互换小说| 少妇熟女欧美另类| av免费观看日本| 中文字幕免费在线视频6| 一区二区av电影网| tube8黄色片| 国产精品欧美亚洲77777| 亚洲精品一二三| 亚洲色图综合在线观看| 老司机影院毛片| 2021少妇久久久久久久久久久| a级毛片在线看网站| 黄网站色视频无遮挡免费观看| 91国产中文字幕| 男人舔女人的私密视频| 一级毛片 在线播放| 国产淫语在线视频| 亚洲av电影在线观看一区二区三区| 不卡视频在线观看欧美| 王馨瑶露胸无遮挡在线观看| 男女免费视频国产| 99热全是精品| 精品国产乱码久久久久久小说| av在线app专区| 国产精品免费大片| 深夜精品福利| 好男人视频免费观看在线| 国产免费一级a男人的天堂| 在线免费观看不下载黄p国产| 日本色播在线视频| 十八禁高潮呻吟视频| 色哟哟·www| 在线精品无人区一区二区三| 免费观看无遮挡的男女| 国产有黄有色有爽视频| 国产黄色视频一区二区在线观看| 日本与韩国留学比较| 九九爱精品视频在线观看| 久久久久视频综合| av视频免费观看在线观看| 免费观看性生交大片5| 在线天堂最新版资源| 一二三四在线观看免费中文在 | 综合色丁香网| 亚洲成人av在线免费| 欧美日韩av久久| 欧美人与性动交α欧美精品济南到 | 一区二区av电影网| 亚洲欧美色中文字幕在线| 极品人妻少妇av视频| 男女午夜视频在线观看 | 精品一区二区三卡| 美女xxoo啪啪120秒动态图| 伦理电影大哥的女人| 春色校园在线视频观看| 亚洲精品自拍成人| 中文字幕亚洲精品专区|