• <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 ?

    Laboratory investigation of the hydroelastic effect on liquid sloshing in rectangular tanks*

    2014-06-01 12:30:01JIANGMeirong蔣梅榮RENBing任冰WANGGuoyu王國玉WANGYongxue王永學(xué)
    關(guān)鍵詞:王國

    JIANG Mei-rong (蔣梅榮), REN Bing (任冰), WANG Guo-yu (王國玉), WANG Yong-xue (王永學(xué))

    State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, Dalian 116024, China, E-mail: meirongjiang@live.cn

    Laboratory investigation of the hydroelastic effect on liquid sloshing in rectangular tanks*

    JIANG Mei-rong (蔣梅榮), REN Bing (任冰), WANG Guo-yu (王國玉), WANG Yong-xue (王永學(xué))

    State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, Dalian 116024, China, E-mail: meirongjiang@live.cn

    (Received July 1, 2013, Revised October 8, 2013)

    A sloshing experiment is conducted to study the hydroelastic effect in an elastic tank. For this purpose, a translational harmonic excitation is applied to a 2-D rectangular tank model. The lowest-order natural frequencies of the liquid in the tank are determined through the sweep test. The wave elevation and the sloshing pressure are obtained by changing the excitation frequency and the liquid depth. Then the characteristics and the variation of the elevation and the pressure are discussed. The results are compared with the experimental results and the theoretical calculations in a rigid tank. Our analysis indicates that, in the nonresonant cases, the elastic results, the rigid experimental results and the theoretical values are all close to each other. In contrast, under the resonant condition, the elastic experimental result is slightly smaller than the rigid one. Also, the theoretical values are smaller than the experimental results at the resonant frequency.

    liquid sloshing, elastic tank, wave elevation, sloshing pressure

    Introduction

    Sloshing must be considered for almost any moving vehicle or structure containing a liquid with a free surface and it can be the result of the resonant excitation of the tank liquid. Since the 1950s, the liquid sloshing in tanks has received a great deal of attention in the fields of the aerospace applications, the naval architectures, the ocean engineering and the civil engineering. Recently, the risk of leakage and the related security problems in the liquefied natural gas (LNG) carriers become increasingly an important issue due to the huge demands on the LNG terminals and the transportation systems all over the world[1].

    Experiments are considered to be the most reliable method to reveal sloshing mechanisms, and the results also serve as the validation data for numerical simulations. A rather comprehensive review and discussion of the analytical and experimental researches was made, mainly focusing on the axially symmetric fuel tanks, as the starting point of the later successive researches in several areas[2].

    There was a considerable amount of work on the 3-D liquid sloshing in the rigid tanks. The results of several research programs investigating sloshing in LNG carriers were delineated, and a three-parameter Weibull distribution was proposed to describe the peak pressure probability distribution[3]. Model tests were reported in which the sloshing forces on the instrumented structural members and the sloshing pressures were measured in shiplike tanks and shiplike internal structures[4]. The 2-D transient sloshing was modeled in the test and compared with the free surface elevation with the multidimensional modal method[5]. A time-resolved particle image velocimetry technique was applied in order to characterize the details of the fluid dynamics, and the wave loads were computed by integrating the experimental pressure distributions[6]. The pressures along the boundaries of the 2-D tanks of different geometries were measured, synchronized with the fast acquisition of images of the flow at the moments and locations of the impacts[7].

    Meanwhile, several studies were carried out on the 3-D effect of the sloshing in rigid tanks. A series of model tests on the transient sloshing were condu-cted, to classify all 3-D nonlinear wave motions[8]. The pressure distribution and the 3-D effect under the pitch[9]and surge excitations[10]were studied in baffled tanks. Sloshing in a cylindrical tank with various fill levels and ring baffles was experimentally investigated, and it was found that ring baffle arrangements were very effective in reducing the sloshing loads[11]. In addition, the coupling effect between the sloshing in rigid tanks and the ship motion was also studied[12,13].

    Liquid sloshing was studied extensively, but mostly focusing on the rigid tanks. The actual tank is elastic and will respond to the sloshing loads[14-16]. For example, in the LNG carriers, the large size bulkheads of the membrane-type tanks are typical elastic structures. The fluid–structure interaction could play an important role in the determination of the sloshing impact load due to the elasticity of the membrane-type containment system. Meanwhile, the safety of the structure can be strongly influenced by the dynamical response, such as the structural strain or movement. Elastic tanks were not extensively studied. Therefore, it is desirable to investigate the sloshing in elastic tanks and the related hydroelastic problems. A large scale test was conducted to analyze the hydroelastic effect[17], and a significant influence of the stiffness on the pressure pulse was observed, which shows that the elastic integrated pressure pulse is about 10% lower than the stiff one but that the peak pressure distributions of the two are very similar. The elasticity of the tank structure was found to have a significant influence on the height and shape of the impact pressure peak in the LNG tank model test[18]. There was no clear tendency for the case where the tank was 30% full but a 12%-19% reduction of impact pressure was observed for the case where the tank was 95% full. The dynamical strain of the copper panel on the rigid LNG tank was analyzed recently[19].

    Fig.1 The sketch of the rectangular tank and the setup of the instrumentation (m)

    Fig.2 The setup of the CCD camera and its use in the test

    Fig.3 A typical experiment acquisition signal of the sweep test (h =0.250 m,A=0.010 m)

    Despite many studies in these directions, the fundamental physics of sloshing in elastic tanks is stillnot well understood. In this paper, a systematic experiment is conducted to explore this subject, and a statistical approach is adopted to analyze the hydroelastic effect of the elastic tank. For this purpose, a physical model test is conducted to study the sloshing in an elastic rectangular tank under translational harmonic excitations. Different liquid depths and excitation frequencies are considered, and then the characteristics of the wave elevation and the sloshing pressure in the tank are discussed. The results are compared with the rigid experimental results and the theoretical calculations.

    Table 1 The lowest-order natural frequency for the liquid depths of h=0.080 m and 0.250 m

    1. Experimental setup

    1.1The model tank and the instrumentation

    The sloshing experiments under translational harmonic excitations are conducted at the State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology. The physical model tanks are mounted on a shaking table, which is capable of performing harmonic and random motions with three degrees of freedom. The working surface of the slip table is 0.500 m×0.500 m, and the range of the excitation amplitude and frequency are 0 m-0.0254 m and 0 Hz-1 000 Hz, respectively.

    Two types of rectangular tanks, rigid and elastic, are modeled in our experiment. The rigid model is made of 0.012 m plexiglass sheets, while for the elastic model, the top, left and right bulkheads are made of 0.002 m plexiglass sheets, and the other parts are made of 0.012 m plexiglass sheets. The internal tank dimensions are L×H×B=0.5 m×0.5 m×0.1m . A sketch of the tank and the coordinate system xoy are shown in Fig.1.

    Clean tap water at room temperature is used as the liquid in the tank. Its density and viscosity are ρ=1.0× 103kg/m3and ν=1.005× 103N· s/m2, respectively. In order to catch the free surface, the red fluorescent dye rhodamine is added to the water; this dye does not affect the density and viscosity of the water.

    The sloshing pressures are measured by using the DS30-MD14 multi-point pressure-measuring system, made by the Research Institute of Water Transportation of Tianjin. All pressure signals are sampled at 1 000 Hz with a precision of ±0.01kPa . Nine pressure transducers are fixed on the bulkhead at different positions in the tank, as shown in Fig.1.

    An image acquisition and data analysis system is designed to catch the free surface, as shown in Fig.2. The CM-140MCL industrial CCD camera from the Japanese company JAI and the 09C lens from Computar in Japan are used in this system, with the Coreco image acquisition card from DALSA Corporation in Canada. Shade cloth is used to block external sources of light and make the room dark, and a projector is set in the upper part of the tank, projecting a sheet of light on the free surface of the liquid from above.

    With the red fluorescent dye Rhodamine in the water, a band of light will be formed on the free surface, while other parts of the liquid below the surface will still be dark. The camera is placed in front of the tank, capturing the band of light on the free surface at 30 frames per second. The images are collected through the acquisition software Sapera CamExpert. Later, a specially written MATLAB procedure for correcting distortions and detecting wave elevations is used to process and analyze the acquired images, and then the wave elevations at the desired points on the right part of the free surface are obtained. Two measuring points, E01 and E02, are shown in Fig.1 with the x coordinates being 0.125 m and 0.240 m, respectively.

    1.2Test cases

    Several cases are tested for two different liquid depths: the shallow liquid depth h=0.080 m (h/ l= 0.16) and the intermediate liquid depth h=0.250 m (h/ l=0.50). The amplitude A is set to several different values: 0.004 m, 0.006 m, 0.008 m and 0.010 m. In order to obtain the periodic steady-state sloshing waves, most test runs last at least 100 s, and the real running time of the test is determined by the excitation period and the specific circumstances of the test.

    Fig.4 Snapshots and comparisons of the experimental and theoretical wave elevations

    Around the primary resonance frequency f0, a relatively wide range of excitation frequencies is selected, between 0.5 Hz and 1.7 Hz. Each test is repeated at least three times, and the mean value of the wave elevation and the sloshing pressure is taken over the three test runs.

    2. Results and discussions

    A linear analytical solution for a rigid tank derived by Faltinsen[20]is employed and compared with the experiment results. This solution is widely used, such as Wu et al.[21], Liu and Lin[22], Ming and Duan[23]and Xue and Lin[24], to verify experimental data and numerical simulations. Here, we compare this theoretical solution with our experimental data, in order to highlight the nonlinearities in the experiment, such as the nonlinear phenomenon of the hydraulic jump, the double-peak phenomenon and the asymmetry of the wave crest and the trough. An artificial damping term is introduced in this approach, which is chosen based on trial-and-error from a variety of parameters in the tank. Different damping coefficients are used in the calculations, and in the case of the damping coefficient equal to 5%, the theoretical solution and the experimental data are most close to each other. Thus, the artificial damping coefficient of 5% is adopted in our calculations. Due to the limitations of the theoretical solution, there are no theoretical values at the measuring positions above the free surface. The experimental wave elevations and sloshing pressures in the elastic tank are analyzed in the time domain, and are compared with the experimental results and the analytical solutions in the rigid tank. The excitation amplitude A maintains the same value (0.006 m) in the following analysis.

    Table 2 The average values of the experimental and theoretical wave elevations (h=0.080 m)

    2.1Free surface elevations

    As discussed in Section 2.1, only the right half of the tank is captured in the CCD images, which are presented as the snapshots of the wave elevation here. Figure 4 shows a snapshot of the wave elevation in the rigid experiment and a comparison of the experimental and theoretical elevations in the tank for the depth h=0.080 m . Under the resonant condition (f= 0.92 Hz, a double-peak phenomenon is observed at the crest of the E01 (x=0.125 m), which results from the joint action of the traveling wave and the water jump. First, a traveling wave propagates forward in the tank, generating the first elevation peak at E01 (see Fig.4(a), t2=83.52s), and then a hydraulic jump is formed when the traveling wave arrives at the bulkhead (t3=83.71s). The second peak is from another traveling wave, which is formed after the collision with the bulkhead and the collapse of the hydraulic jump on the bulkhead, propagating in the opposite direction (t4=83.87 s). By adopting the PIV technique, Lugni[6]described a similar process of the wave impact in a rigid tank. The physical phenomenon of the experimental wave elevation in the elastic tank is almost the same as that in the rigid tank, but its magnitude is slightly less than the rigid result by 7.19%, as shown in Table 2. The analytical solution is a regular cosine curve, and its magnitude is less than the magnitude in the test. At the position E02 (x=0.240 m), the crest is larger and sharper, while the trough is smaller and flatter, which is due to the nonlinear effect of the hydraulic jump near the bulkhead. In this case, the experimental elevation in the elastic tank is also less than that in the rigid tank by 21.31%, as shown in Table 2. The analytical solution is still a regular cosine curve, the magnitude of which is smaller than the experimental result.

    Fig.5 Snapshots and comparisons of the experimental and theoretical wave elevations

    Figure 5 shows snapshots of the wave elevation in the rigid experiment and comparisons of the experimental and theoretical elevations in the tank of the depth h=0.250 m . Under the resonant condition (f=1.11Hz), a large-amplitude asymmetric standing wave is observed on the free surface, accompanying the traveling wave, and overturns the free surface, as well as causing waves to impact on the tank roof. (Thedash-dotted line in Fig.5(b) represents the position of the tank roof, y=0.250 m ) This hit on the tank ceiling was also observed by Faltinsen[5]for a rigid tank. The physical process of the experimental wave elevation in the elastic tank is almost the same as that in the rigid tank. The wave elevations in the elastic tank are less than those in the rigid tank by 6.86% at the position E01 and by 3.10% at the position E02, and the experimental value is much greater than the theoretical value, as shown in Table 3. This suggests that the wave elevation of the liquid in the model tank is changed due to the influence of the fluid–tank interaction. The maximum wave crest (0.25 m) of the experimental result is 4.7 times as much as that (0.0533 m) of the analytical solution.

    Table 3 The average values of the experimental and theoretical wave elevations (h=0.250 m)

    The average value of the crest ηc,avgis chosen as the characteristic value to use in the statistical analysis of the wave elevation in the steady or quasi-steady state. Figure 6 shows the variation of the elevation versus different excitation frequencies at the liquid depths of h=0.080 m and 0.250 m. This indicates that the trends of the experimental results and that of the theoretical result are almost the same. When the excitation frequency f changes from the non-resonant frequency to the lowest-order natural frequency of the liquid, the wave crest increases gradually, achieving the maximum around the lowest-order resonance frequency f0. The increase of the wave crest is slow and flat in the non-resonant region, while it is substantial in the resonant region.

    When the excitation frequency is far away from the lowest-order natural frequency of the liquid in the tank, the elastic experimental result, the rigid experimental result and the theoretical value are all relatively close to each other. As discussed in Section 2.2, the theoretical resonance frequency, the rigid and the elastic experimental resonance frequencies are 0.85 Hz, 0.92 Hz and 0.89 Hz, respectively, at the shallow liquid depth (h=0.080 m). For the intermediate liquid depth (h=0.250 m), the corresponding frequencies are 1.20 Hz, 1.11 Hz and 1.11 Hz, respectively. When the excitation frequency approaches the lowest-order natural frequency, the experimental elevations in the elastic tank are slightly less than those in the rigid tank. In addition, the theoretical values are smaller than the experimental results under the resonant frequencies at the two depths.

    Fig.6 Wave elevations in the experiment and the analytical solution versus excitation frequencies

    Fig.7 Comparisons of the experimental and theoretical pressures (h =0.080 m,f=0.89 Hz)

    2.2 Sloshing pressure

    At the static liquid level, the recorded value of the pressure transducer is zero when the water falls below this level. Therefore, for the measuring points at this level, only the positive pressures are analyzed when the analytical solution is compared with the experimental result. In order to facilitate the check and the comparison between the rigid and the elastic pressures, a phase is set to a reasonable value and modulated in the time-history curves, and the resulting phase difference does not appear in the actual data.

    Table 4 The 1/3 maximum peak pressure of the theoretical and test results (h=0.080 m)

    Fig.8 Comparisons of the experimental and theoretical pressures (h =0.250 m,f=1.11Hz)

    Table 5 The 1/3 maximum peak pressure of the theoretical and test results (h=0.250 m)

    When the excitation frequency is far away from the lowest-order natural frequency of the liquid, the elastic experimental result, the rigid experimental result and the theoretical values are all relatively close to each other. The theoretical resonance frequency and the rigid and elastic experimental resonance frequencies are given in Section 3.1 and are not repeated here. While the excitation frequency approaches the lowestorder natural frequency, the sloshing pressures on the elastic bulkhead are slightly smaller than those on the rigid bulkhead. In addition, the theoretical values are smaller than the experimental results under the resonant frequencies at the two depths.

    3. Conclusions

    A physical model test is conducted to study the hydroelastic effect of the sloshing in the elastic tank under translational harmonic excitation. The results are compared with the experimental results for a rigid tank and with theoretical calculations. The following conclusions can be drawn.

    Fig.9 Pressures in the experiments and the analytical solution versus excitation frequencies

    (1) There is no significant difference between the experimental lowest-order natural frequencies of the liquid in the elastic tank and in the rigid tank, but these two frequencies slightly deviate from the theoretical value in the rigid tank. At the shallow liquid depth (h/ l=0.16), the experimental frequencies are slightly greater than the theoretical one by about 5%, however, at the intermediate depth (h/ l=0.50), they are less than the theoretical one by 5%-10%.

    (2) In the non-resonant cases, the elastic and the rigid experimental wave elevations and the theoretical values are all relatively close to each other. Under the resonant condition, the experimental elevations in the elastic tank are slightly less than those in the rigid tank. Further, the theoretical values are smaller than the experimental results at the two depths.

    (3) In the non-resonant cases, the elastic and the rigid experimental sloshing pressures and the theoretical values are all relatively close to each other. Under the resonant condition, the experimental sloshing pressures on the elastic bulkhead are slightly smaller than those on the rigid bulkhead, and the theoretical values are smaller than the experimental results.

    [1] GAVORY T., DE SEZE P. E. Sloshing in membrane LNG carriers and its consequences from a designer’s perspective[C]. Proceedings of the 19th International Offshore and Polar Engineering Conference. Osaka, Japan, 2009, 13-20.

    [2] ABRAMSON H. N. The dynamic behavior of liquids in moving containers[R]. NASA Report, SP 106, 1966.

    [3] ABRAMSON H. N., BASS R. L. and FALTINSEN O. M. et al. Liquid slosh in LNG carriers[C]. The 10thSymposium on Naval Hydrodynamics. Cambridge, USA, 1974, ACR-204, 371-388.

    [4] HAMLIN N. A., LOU Y. K. and MACLEAN W. M. et al. Liquid sloshing in slack ship tanks-Theory, observations, and experiments[J]. SNAME Transactions, 1986, 94: 159-195.

    [5] FALTINSEN O. M., ROGNEBAKKE O. F. and LUKOVSKY I. A. et al. Multidimensional modal analysis of nonlinear sloshing in a rectangular tank with finite water depth[J]. Journal of Fluid Mechanicas, 2000, 407: 201-234.

    [6] LUGNI C., BROCCHINI M. and FALTINSEN O. M. Wave impact loads: The role of the flip-through[J]. Physics of Fluid, 2006, 18(12): 122101.

    [7] PISTANI F., THIAGARAJAN K. Experimental measurements and data analysis of the impact pressures in a sloshing experiment[J]. Ocean Engineering, 2012, 52: 60-74.

    [8] FALTINSEN O. M., ROGNEBAKKE O. F. and TIMOKHA A. N. Resonant three-dimensional nonlinear sloshing in a square-base basin[J]. Journal of Fluid Mechanicas, 2003, 487: 1-42.

    [9] AKYILDIZ H., UNAL E. Experimental investigation of pressure distribution on a rectangular tank due to the liquid sloshing[J]. Ocean Engineerring, 2005, 32(11-12): 1503-1516.

    [10] PANIGRAHY P. K., SAHA U. K. and MAITY D. Experimental studies on sloshing behavior due to horizontal movement of liquids in baffled tanks[J]. Ocean Engineering, 2009, 36(3-4): 213-222.

    [11] AKYILDIZ H., UNAL E. and AKSOY H. An experimental investigation of the effects of the ring baffles on liquid sloshing in a rigid cylindrical tank[J]. Ocean Engineering, 2013, 59(1): 190-197.

    [12] ROGNEBAKKE O. F., FALTINSEN O. M. Coupling of sloshing and ship motions[J]. Journal of Ship Research, 2003, 47(3): 208-221.

    [13] KIM Y., NAM B. W. and KIM D. W. et al. Study on coupling effects of ship motion and sloshing[J]. Ocean Engineering, 2007, 34(16): 2176-2187.

    [14] FALTINSEN O. M., TIMOKHA A. N. Sloshing[M]. New York, USA: Cambridge University Press, 2009.

    [15] LEE D. Y., CHOI H. S. Study on sloshing in cargo tanks including hydroelastic effects[J]. Journal of Marine Science and Technology, 1999, 4: 27-34.

    [16] ZHU Ren-qing. Time domain simulation of liquid sloshing and its interaction with flexible structure[D]. Doctoral Thesis, Wuxi, China: China Ship Scientific Research Center, 2001(in Chinese).

    [17] BUNNIK T., HUIJSMANS R. Large scale LNG sloshing model tests[C]. Proceedings of the 17th International Offshore and Polar Engineering Conference. Lisbon, Portugal, 2007, 1893-1899.

    [18] JUNG J. J., LEE H. H. and PARK T. H. et al. Experimental and numerical investigation into the effects of fluid-structure interaction on the sloshing impact loads in member LNG carrier[C]. Proceedings of the ASME 27th International Conference on Offshore Mechanics and Arctic Engineering. Estoril, Portugal, 2008.

    [19] QI En-rong, PANG Jian-hua and XU Chun et al. Experimental study of sloshing pressure and structural response in membrane LNG tanks[J]. Ship Science and Technology, 2011, 33(4): 29-38(in Chinese).

    [20] FALTINSEN O. M. A numerical nonlinear method of sloshing in tanks with two-dimensional flow[J]. Journal of Ship Research, 1978, 22(3): 193-202.

    [21] WU G., MA Q. and TAYLOR R. E. Numerical simulation of sloshing waves in a 3D tank based on a finite element method[J]. Applied Ocean Research, 1998, 20(6): 337-355.

    [22] LIU D., LIN P. A numerical study of three-dimensional liquid sloshing in tanks[J]. Journal of Computational Physics, 2008, 227(8): 3921-3939.

    [23] MING Ping-jian, DUAN Wen-yang. Numerical simulation of sloshing in rectangular tank with VOF based on unstructured grids[J]. Journal of Hydrodynamics, 2010, 22(6): 856-864.

    [24] XUE M., LIN P. Numerical study of ring baffle effects on reducing violent liquid sloshing[J]. Computers and Fluids, 2011, 52(1): 116-129.

    10.1016/S1001-6058(14)60084-6

    * Project supported by the National Natural Science Foundation of China (Grant No. 51179030, 51309038).

    Biography: JIANG Mei-rong (1983-), Male, Ph. D. Candidate

    REN Bing, E-mail: bren@dlut.edu.cn

    猜你喜歡
    王國
    幾何王國歡樂多
    幾何王國歡樂多
    誤入神秘王國
    井然有序
    綠色天府(2022年7期)2022-08-16 09:08:22
    一滴水中的王國
    趣味(語文)(2020年5期)2020-11-16 01:34:54
    地下王國
    她的2000億打工王國
    逃離鼠王國
    建立新王國
    NBA特刊(2018年21期)2018-11-24 02:47:48
    最威風(fēng)的王國
    午夜激情久久久久久久| 国产日韩欧美视频二区| 国产精品久久久久久精品电影小说| 纯流量卡能插随身wifi吗| 久久中文看片网| 亚洲人成77777在线视频| 少妇裸体淫交视频免费看高清 | 一区二区三区精品91| 国产在线免费精品| 免费在线观看完整版高清| www.999成人在线观看| 中文字幕人妻丝袜一区二区| 一个人免费在线观看的高清视频 | 丰满人妻熟妇乱又伦精品不卡| 国产男人的电影天堂91| 免费女性裸体啪啪无遮挡网站| 中亚洲国语对白在线视频| 这个男人来自地球电影免费观看| 国产国语露脸激情在线看| 欧美国产精品一级二级三级| 少妇猛男粗大的猛烈进出视频| 五月天丁香电影| 亚洲精品中文字幕在线视频| 精品亚洲成a人片在线观看| www.999成人在线观看| av网站免费在线观看视频| 黄色视频在线播放观看不卡| 国产日韩欧美视频二区| 午夜福利视频在线观看免费| 国产免费av片在线观看野外av| 99国产精品免费福利视频| 成人免费观看视频高清| 久久国产精品大桥未久av| 久久免费观看电影| a在线观看视频网站| 精品一区二区三区四区五区乱码| 日本猛色少妇xxxxx猛交久久| 午夜免费鲁丝| 悠悠久久av| 99国产精品免费福利视频| 国产一区二区三区av在线| 欧美大码av| 亚洲精品第二区| 午夜福利乱码中文字幕| 亚洲精品久久久久久婷婷小说| 法律面前人人平等表现在哪些方面 | 一二三四在线观看免费中文在| tube8黄色片| 丝袜美腿诱惑在线| 一级片'在线观看视频| 国产精品熟女久久久久浪| 天天影视国产精品| 这个男人来自地球电影免费观看| 正在播放国产对白刺激| 亚洲中文字幕日韩| 亚洲精品国产精品久久久不卡| 一区在线观看完整版| 亚洲国产中文字幕在线视频| 日韩一区二区三区影片| 久久中文看片网| 成年人免费黄色播放视频| 精品久久久精品久久久| 精品国产乱子伦一区二区三区 | 99久久人妻综合| 久久狼人影院| 亚洲精品美女久久久久99蜜臀| 久久人妻福利社区极品人妻图片| 大香蕉久久成人网| 国产成人免费观看mmmm| 国产成人免费观看mmmm| 一二三四社区在线视频社区8| 国产精品.久久久| 交换朋友夫妻互换小说| 美女主播在线视频| 老司机午夜福利在线观看视频 | 欧美精品一区二区大全| tocl精华| av又黄又爽大尺度在线免费看| 91老司机精品| 欧美 亚洲 国产 日韩一| 婷婷成人精品国产| 欧美av亚洲av综合av国产av| 男女无遮挡免费网站观看| 亚洲男人天堂网一区| 中文字幕另类日韩欧美亚洲嫩草| 黄片大片在线免费观看| 夜夜夜夜夜久久久久| 91大片在线观看| 在线观看舔阴道视频| 建设人人有责人人尽责人人享有的| 亚洲少妇的诱惑av| 久久亚洲国产成人精品v| 精品国产乱码久久久久久男人| 国产黄频视频在线观看| 各种免费的搞黄视频| xxxhd国产人妻xxx| 国产精品久久久久久精品电影小说| 亚洲精品国产av蜜桃| 精品视频人人做人人爽| 国产精品.久久久| 视频在线观看一区二区三区| 日韩制服骚丝袜av| 精品第一国产精品| 国产精品熟女久久久久浪| 老熟妇仑乱视频hdxx| 久久久精品免费免费高清| 国内毛片毛片毛片毛片毛片| 一区二区三区精品91| 国产欧美日韩综合在线一区二区| 国产成人啪精品午夜网站| 大片免费播放器 马上看| 婷婷成人精品国产| 久久精品熟女亚洲av麻豆精品| 国产欧美亚洲国产| 麻豆av在线久日| 99热网站在线观看| 精品一区二区三区av网在线观看 | 少妇猛男粗大的猛烈进出视频| 精品久久久精品久久久| 亚洲专区中文字幕在线| 国产伦理片在线播放av一区| 亚洲国产精品999| 国产一级毛片在线| 亚洲全国av大片| 国产精品久久久久久精品古装| 亚洲欧美色中文字幕在线| 精品少妇黑人巨大在线播放| 成人手机av| 国产精品免费大片| 亚洲专区字幕在线| 在线观看人妻少妇| 精品少妇黑人巨大在线播放| 中文字幕人妻丝袜制服| 极品人妻少妇av视频| 天堂8中文在线网| 久久国产精品影院| 日本五十路高清| 精品视频人人做人人爽| 国产精品二区激情视频| 免费女性裸体啪啪无遮挡网站| 老鸭窝网址在线观看| 欧美人与性动交α欧美精品济南到| av天堂久久9| 无限看片的www在线观看| 国产无遮挡羞羞视频在线观看| 极品少妇高潮喷水抽搐| 久久亚洲精品不卡| 岛国毛片在线播放| 国产福利在线免费观看视频| 国产欧美日韩一区二区精品| 色综合欧美亚洲国产小说| 精品少妇久久久久久888优播| 一区二区三区乱码不卡18| 亚洲成人免费电影在线观看| 99国产极品粉嫩在线观看| 美女中出高潮动态图| 精品少妇黑人巨大在线播放| 久久久久久久久久久久大奶| 久久香蕉激情| 极品人妻少妇av视频| 亚洲精品国产色婷婷电影| 美女福利国产在线| 手机成人av网站| 亚洲三区欧美一区| av在线app专区| 国产不卡av网站在线观看| 老司机影院毛片| 午夜福利在线观看吧| 99久久国产精品久久久| 国产精品一区二区在线不卡| 精品卡一卡二卡四卡免费| 麻豆乱淫一区二区| 精品人妻1区二区| 少妇被粗大的猛进出69影院| 日韩三级视频一区二区三区| 大陆偷拍与自拍| 最新的欧美精品一区二区| 亚洲国产av影院在线观看| 熟女少妇亚洲综合色aaa.| 久久99热这里只频精品6学生| 亚洲欧美清纯卡通| 水蜜桃什么品种好| 天天躁夜夜躁狠狠躁躁| 美女午夜性视频免费| 日韩三级视频一区二区三区| 亚洲一码二码三码区别大吗| 欧美人与性动交α欧美精品济南到| 精品久久蜜臀av无| 久久久久久久久免费视频了| 久久精品亚洲熟妇少妇任你| 欧美亚洲日本最大视频资源| 美女中出高潮动态图| 日韩欧美一区视频在线观看| 99re6热这里在线精品视频| 国产成人精品久久二区二区91| 视频区图区小说| 欧美久久黑人一区二区| 我要看黄色一级片免费的| 热re99久久精品国产66热6| 丁香六月天网| 午夜福利,免费看| 最近最新中文字幕大全免费视频| 美女主播在线视频| 国产成人啪精品午夜网站| 黄色毛片三级朝国网站| 国产精品1区2区在线观看. | 欧美变态另类bdsm刘玥| 一二三四社区在线视频社区8| 啪啪无遮挡十八禁网站| av福利片在线| 亚洲欧洲日产国产| 国产免费一区二区三区四区乱码| 亚洲中文字幕日韩| 亚洲国产看品久久| 国产精品九九99| 汤姆久久久久久久影院中文字幕| av又黄又爽大尺度在线免费看| 男男h啪啪无遮挡| 黄色 视频免费看| 91麻豆精品激情在线观看国产 | 一二三四在线观看免费中文在| 日本五十路高清| 91精品三级在线观看| 老鸭窝网址在线观看| 一本色道久久久久久精品综合| 法律面前人人平等表现在哪些方面 | 亚洲精品一卡2卡三卡4卡5卡 | 久久精品亚洲av国产电影网| 啦啦啦视频在线资源免费观看| 97在线人人人人妻| 日韩视频一区二区在线观看| 国产精品免费大片| 一区二区三区激情视频| 亚洲精品美女久久久久99蜜臀| 国产av又大| 国产高清videossex| 午夜精品国产一区二区电影| 欧美日本中文国产一区发布| 成年人黄色毛片网站| 色视频在线一区二区三区| 欧美激情久久久久久爽电影 | 成人影院久久| 久久人人爽人人片av| 亚洲精品久久久久久婷婷小说| 亚洲欧美成人综合另类久久久| 欧美中文综合在线视频| 日韩免费高清中文字幕av| 精品亚洲成国产av| 国内毛片毛片毛片毛片毛片| 欧美黄色淫秽网站| 亚洲国产精品成人久久小说| 久久精品aⅴ一区二区三区四区| 永久免费av网站大全| 国产亚洲午夜精品一区二区久久| 真人做人爱边吃奶动态| 老汉色∧v一级毛片| 久久久水蜜桃国产精品网| 一区二区三区精品91| 国精品久久久久久国模美| 丝袜在线中文字幕| 日韩,欧美,国产一区二区三区| 久久久国产成人免费| 国产1区2区3区精品| 亚洲伊人色综图| 老司机影院毛片| 一进一出抽搐动态| 中国国产av一级| 精品少妇一区二区三区视频日本电影| 欧美变态另类bdsm刘玥| 男女边摸边吃奶| 中文字幕色久视频| 欧美 亚洲 国产 日韩一| 亚洲欧美色中文字幕在线| 美女脱内裤让男人舔精品视频| 后天国语完整版免费观看| 我的亚洲天堂| 日韩一区二区三区影片| 亚洲成人国产一区在线观看| 亚洲激情五月婷婷啪啪| 国产亚洲午夜精品一区二区久久| 免费在线观看视频国产中文字幕亚洲 | 男女午夜视频在线观看| 免费女性裸体啪啪无遮挡网站| 性少妇av在线| 亚洲av成人一区二区三| 99国产极品粉嫩在线观看| 国产有黄有色有爽视频| 亚洲欧美成人综合另类久久久| 国产99久久九九免费精品| 国产一级毛片在线| 国产欧美亚洲国产| 精品一区二区三区四区五区乱码| 咕卡用的链子| 狠狠精品人妻久久久久久综合| 人妻 亚洲 视频| 久久久久国内视频| 国产精品欧美亚洲77777| 欧美激情久久久久久爽电影 | 精品国产乱码久久久久久小说| 国产高清videossex| 一边摸一边做爽爽视频免费| 人妻一区二区av| 香蕉国产在线看| 少妇猛男粗大的猛烈进出视频| 国产欧美日韩一区二区三区在线| 99国产精品免费福利视频| 久久久国产成人免费| 日日夜夜操网爽| 成年av动漫网址| 久久国产精品大桥未久av| 中文欧美无线码| 欧美国产精品一级二级三级| 久久久久久久久免费视频了| 一区二区三区激情视频| 欧美黑人精品巨大| 啪啪无遮挡十八禁网站| 爱豆传媒免费全集在线观看| av免费在线观看网站| 国产在线观看jvid| 黄色视频,在线免费观看| 极品人妻少妇av视频| 窝窝影院91人妻| 午夜视频精品福利| 啦啦啦 在线观看视频| 国产精品秋霞免费鲁丝片| 日韩免费高清中文字幕av| 不卡一级毛片| www.av在线官网国产| 99热国产这里只有精品6| 久久 成人 亚洲| 久久久久久久大尺度免费视频| 久久久久精品人妻al黑| 99精品久久久久人妻精品| 天堂8中文在线网| 国产欧美日韩一区二区三区在线| 女人久久www免费人成看片| 日韩制服骚丝袜av| 一本久久精品| 精品视频人人做人人爽| 久久久久久久久久久久大奶| 国产精品一区二区在线不卡| 成年av动漫网址| 亚洲av电影在线进入| 在线av久久热| 久久精品亚洲熟妇少妇任你| 国产又爽黄色视频| a级毛片在线看网站| 搡老乐熟女国产| 999久久久精品免费观看国产| 国产一区二区三区综合在线观看| 久久免费观看电影| av天堂久久9| 狠狠精品人妻久久久久久综合| 成在线人永久免费视频| 日本猛色少妇xxxxx猛交久久| 亚洲熟女毛片儿| 成年人免费黄色播放视频| 99久久精品国产亚洲精品| 亚洲一区中文字幕在线| 精品人妻在线不人妻| 最近最新中文字幕大全免费视频| 各种免费的搞黄视频| 亚洲午夜精品一区,二区,三区| 男女无遮挡免费网站观看| 国产福利在线免费观看视频| 女警被强在线播放| 欧美一级毛片孕妇| 国产成+人综合+亚洲专区| 亚洲熟女毛片儿| 亚洲成人国产一区在线观看| 桃红色精品国产亚洲av| 亚洲av电影在线观看一区二区三区| 国产亚洲av高清不卡| 久久人妻熟女aⅴ| 中文字幕av电影在线播放| 亚洲国产毛片av蜜桃av| 午夜精品久久久久久毛片777| 亚洲五月色婷婷综合| 最近中文字幕2019免费版| 中文字幕色久视频| 性色av一级| 欧美在线一区亚洲| 中文字幕高清在线视频| 亚洲成av片中文字幕在线观看| 国产国语露脸激情在线看| 午夜激情av网站| 精品亚洲成国产av| 91国产中文字幕| 91精品伊人久久大香线蕉| avwww免费| av片东京热男人的天堂| 久久久久网色| 亚洲,欧美精品.| 黄色片一级片一级黄色片| 国产精品1区2区在线观看. | 久久久久国产一级毛片高清牌| av不卡在线播放| 人妻 亚洲 视频| tocl精华| 91九色精品人成在线观看| 欧美在线黄色| a在线观看视频网站| 日日爽夜夜爽网站| 丁香六月天网| 人成视频在线观看免费观看| 国产精品欧美亚洲77777| 国产精品国产三级国产专区5o| www.999成人在线观看| 一区二区av电影网| 亚洲精品国产av成人精品| 国产xxxxx性猛交| 中文字幕另类日韩欧美亚洲嫩草| 在线观看免费午夜福利视频| 91精品伊人久久大香线蕉| av线在线观看网站| 日韩视频一区二区在线观看| 99久久精品国产亚洲精品| netflix在线观看网站| 亚洲伊人色综图| 黄频高清免费视频| 精品久久蜜臀av无| 老司机亚洲免费影院| 美女中出高潮动态图| 国产精品久久久久久人妻精品电影 | 亚洲专区中文字幕在线| 天天添夜夜摸| 一本—道久久a久久精品蜜桃钙片| 高清欧美精品videossex| 亚洲国产毛片av蜜桃av| 99国产精品一区二区蜜桃av | 黄色视频在线播放观看不卡| 欧美变态另类bdsm刘玥| 最近最新免费中文字幕在线| 最近最新免费中文字幕在线| 日本av免费视频播放| 中国国产av一级| 蜜桃国产av成人99| 狠狠狠狠99中文字幕| av在线播放精品| avwww免费| 亚洲七黄色美女视频| 男人操女人黄网站| 热99国产精品久久久久久7| 日韩欧美一区视频在线观看| 99热网站在线观看| 久久久精品区二区三区| 国产欧美日韩精品亚洲av| 搡老乐熟女国产| 亚洲第一av免费看| 国产精品偷伦视频观看了| 黑人欧美特级aaaaaa片| 涩涩av久久男人的天堂| 美女大奶头黄色视频| 亚洲avbb在线观看| 免费在线观看视频国产中文字幕亚洲 | 男人舔女人的私密视频| 国产免费福利视频在线观看| 老司机福利观看| 好男人电影高清在线观看| 国产有黄有色有爽视频| 黄色a级毛片大全视频| 欧美午夜高清在线| 亚洲第一欧美日韩一区二区三区 | 丰满迷人的少妇在线观看| 午夜精品国产一区二区电影| 俄罗斯特黄特色一大片| 精品久久蜜臀av无| 麻豆乱淫一区二区| 精品国产乱码久久久久久男人| 国产男人的电影天堂91| 一二三四在线观看免费中文在| 男女床上黄色一级片免费看| 国产成人免费观看mmmm| 欧美激情久久久久久爽电影 | av片东京热男人的天堂| 黄色a级毛片大全视频| 久久精品国产a三级三级三级| 嫁个100分男人电影在线观看| 曰老女人黄片| 国产免费现黄频在线看| 中文字幕最新亚洲高清| 亚洲 国产 在线| 大型av网站在线播放| 久久国产精品人妻蜜桃| 两个人免费观看高清视频| 麻豆国产av国片精品| 亚洲欧美激情在线| 满18在线观看网站| 大码成人一级视频| 国产日韩欧美在线精品| 99热国产这里只有精品6| 秋霞在线观看毛片| 精品福利永久在线观看| 99久久综合免费| 深夜精品福利| 国产片内射在线| 少妇粗大呻吟视频| 精品亚洲成a人片在线观看| 最新的欧美精品一区二区| av电影中文网址| 国产精品九九99| 国产精品 欧美亚洲| 亚洲专区中文字幕在线| 亚洲av国产av综合av卡| 咕卡用的链子| 精品少妇黑人巨大在线播放| 中文精品一卡2卡3卡4更新| 丝瓜视频免费看黄片| 国产国语露脸激情在线看| 每晚都被弄得嗷嗷叫到高潮| 十八禁人妻一区二区| 一级黄色大片毛片| 日本a在线网址| 精品一区二区三区av网在线观看 | 国产日韩一区二区三区精品不卡| 欧美av亚洲av综合av国产av| 午夜精品久久久久久毛片777| 侵犯人妻中文字幕一二三四区| 少妇裸体淫交视频免费看高清 | 少妇被粗大的猛进出69影院| 一本—道久久a久久精品蜜桃钙片| 悠悠久久av| 国产成人影院久久av| 亚洲欧美清纯卡通| 国产精品自产拍在线观看55亚洲 | 亚洲成人国产一区在线观看| 少妇的丰满在线观看| 黄色 视频免费看| 亚洲av国产av综合av卡| 丝袜脚勾引网站| 性色av乱码一区二区三区2| 精品卡一卡二卡四卡免费| 在线天堂中文资源库| 久久热在线av| 热99久久久久精品小说推荐| 欧美日韩亚洲国产一区二区在线观看 | 亚洲欧美精品综合一区二区三区| 国产99久久九九免费精品| 日韩免费高清中文字幕av| av有码第一页| 50天的宝宝边吃奶边哭怎么回事| 精品人妻在线不人妻| 99热网站在线观看| 久久久久久久国产电影| tocl精华| 一区二区三区激情视频| 日韩人妻精品一区2区三区| 女性被躁到高潮视频| 超碰成人久久| av有码第一页| 久久国产亚洲av麻豆专区| 欧美日本中文国产一区发布| 精品一区在线观看国产| 男女无遮挡免费网站观看| 各种免费的搞黄视频| av天堂在线播放| 精品一区二区三区四区五区乱码| 蜜桃国产av成人99| 汤姆久久久久久久影院中文字幕| 老熟妇乱子伦视频在线观看 | 久久人妻熟女aⅴ| 天天躁日日躁夜夜躁夜夜| 美女高潮到喷水免费观看| 久久国产亚洲av麻豆专区| 在线天堂中文资源库| 国产精品一区二区免费欧美 | 欧美一级毛片孕妇| av天堂在线播放| 国产一区二区在线观看av| 成人国产一区最新在线观看| 后天国语完整版免费观看| 性色av一级| 国产免费福利视频在线观看| 中国国产av一级| 日韩欧美一区视频在线观看| 日韩一卡2卡3卡4卡2021年| 亚洲熟女毛片儿| 亚洲精华国产精华精| 久久久久国产精品人妻一区二区| 嫁个100分男人电影在线观看| 女人被躁到高潮嗷嗷叫费观| 午夜老司机福利片| 搡老岳熟女国产| 亚洲国产精品一区三区| 久久久久精品人妻al黑| 亚洲午夜精品一区,二区,三区| 国产亚洲欧美在线一区二区| av电影中文网址| 久久人妻福利社区极品人妻图片| 我要看黄色一级片免费的| 国产精品 国内视频| 久热爱精品视频在线9| 后天国语完整版免费观看| 日韩制服丝袜自拍偷拍| 国产97色在线日韩免费| 国产精品香港三级国产av潘金莲| 国产男女内射视频| 高清视频免费观看一区二区| av在线播放精品| 一个人免费在线观看的高清视频 | 午夜影院在线不卡| 男女高潮啪啪啪动态图| 成年人免费黄色播放视频| 99九九在线精品视频| 99国产精品一区二区蜜桃av | 久久性视频一级片| 老熟妇仑乱视频hdxx| 国产成人av教育| 亚洲精品一区蜜桃| 欧美黄色淫秽网站| 在线观看一区二区三区激情| av网站在线播放免费| 国产一卡二卡三卡精品| 国产av国产精品国产| 久久人妻福利社区极品人妻图片|