• <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 Simulation and Analysis of Electromagnetic Fields Induced by a Moving Ship Based on a Three-Layer Geoelectric Model

    2020-11-30 04:43:18SHAOGuihangandLIYuguo
    Journal of Ocean University of China 2020年6期

    SHAO Guihang, and LI Yuguo, 2), *

    Numerical Simulation and Analysis of Electromagnetic Fields Induced by a Moving Ship Based on a Three-Layer Geoelectric Model

    SHAO Guihang1), and LI Yuguo1), 2), *

    1),,,,266100,2),,266237,

    In this paper, we present a numerical simulation method of electromagnetic (EM) fields induced by a moving ship (EMFMS), which consist of both the shaft-rate EM field and the static EM field. The shaft-rate EM fields in the frequency domain are first obtained by solving the partial differential equations together with suitable boundary conditions, and then they are transformed into the time domain by using the inverse Fourier transform. Finally, the static fields are added to obtain the EM fields of a moving ship. The effects of the source current intensity and the source position on the EM fields of a moving ship are discussed in detail. A field example of EM response of a moving ship is presented and its characteristics are analyzed.

    moving ship; shaft-rate EM field; static EM field; numerical simulation

    1 Introduction

    In order to prevent seawater corrosion, ships are often equipped with cathodic protection devices. The currents pro- duced by cathodic protection devices usually form two circuits as shown in Fig.1 (Jeffrey and Brooking, 1999). The one flowing through the ship’s propeller is modulated by the varying bearing resistance, and generates shaft-rate electromagnetic fields (Holtham., 1999). The other flowing through the ship’s coating damage point generates static electromagnetic fields (Nain., 2013). Thus, the electric and magnetic fields induced by a moving ship (EMFMS) consist of both the shaft-rate field and the sta- tic field.

    The study of ship’s EM fields began in the 1960s (Zolotarevskii., 2005), and many studies on EMFMS have been conducted since then (Holmes, 2006). In these studies, however, simulation problems are often simplified. For instance, the geoelectric model is designed as an air- sea two-layer model (Sun., 2003; Lu., 2004; Liu., 2004; Zhang and Wang, 2016), in which the current source of a moving ship is assumed to be equivalent to a horizontal electric dipole (Lu., 2005; Ni., 2006), or the shaft-rate EM fields are neglected (Bao., 2011; Li., 2012). Although these simplifications can reduce the complexity of numerical simulation, they donot sufficiently simulate the real situation. Therefore, three types of problems can be caused by the simplifications. Firstly, in shallow water areas, the seafloor sediment layer has a great influence on the EM responses of a moving ship, hence the two-layer model is improper. Secondly, since the location of the ship’s propeller is different from the coating damage points (Liu, 2009; Cheng., 2016), the ship cannot be equivalent to a horizontal electric dipole. Third, the EM fields of a moving ship consist of both the shaft-rate field and the static field, so both of them should be considered.

    In this paper, we consider an air-seawater-seafloor three- layer geoelectric model. Both the shaft-rate field and the static field are simulated in the frequency domain by using both the horizontal and vertical electric dipoles, then the results are transformed into the time domain by using the inverse Fourier transform, and the EMFMS are obtained by adding the shaft-rate field to the static field. Finally, the shaft-rate field and the static field are separated from the measured EMFMS data, and the characteristics of them are discussed.

    2 Simulation of the EMFMS

    2.1 Theory

    The EMFMS consists of the shaft-rate EM field and the static EM field. They can be approximated by the EM fields of the tilted electric dipole source in the air-sea- seafloor three-layer geoelectric model (Fig.2a). The EM fields generated by a tilted dipole source can be seen as the superposition of those caused by the horizontal and vertical electric dipoles (Fig.2b), and can be expressed as

    where,,andare EM fields generated by the horizontal and vertical electric dipoles, respe- ctively.

    The electromagnetic fields generated by both the horizontal electric dipole (HED) and vertical electric dipole (VED) sources in the layered earth have been well studied (Li and Li, 2016).

    To obtain the EMFMS, both the shaft-rate field and the static field need to be transformed into time domain from frequency domain. Assuming that a ship starts to move at time1and position1along the-axis at a constant velocity, the ship’s position at timet(Fig.3a) can be expressed as:

    where t1, x1and v are known. The ship arrives at location xi at time ti, and ri is the distance from the mid-point of an electric dipole source to a receiver positioned at the seafloor.

    The procedure for calculating the EMFMS is listed as follows.

    1) Calculate shaft-rate fields(x,) (=1, 2,…,) in the frequency domain;

    Fig.2 Schematic diagrams of (a) a moving ship in the air-sea-seafloor three-layer geoelectric model and (b) electric dipole vector decomposition.

    Fig.3 Schematic diagrams of (a) three-layer model for a moving ship and (b) the shaft-rate EM fields in the time domain.

    2) Transform(x,) into time domain response(x,t) (,=1, 2,…,, note thatandare not equal all the time) (shown as red lines in Fig.3b) by using the discrete inverse Fourier transform (Press., 1992), and get the EM field(x,t) (shown as black point in Fig.3b), which is the shaft-rate part of EMFMS;

    3) Set the source frequency to 0 and calculate the static field(x) (=1, 2,…,), then get the time domain static field(t) according to Eq. (3);

    4) Get EMFMS by adding the shaft-rate field(x,t) to static field(t).

    2.2 Numerical Examples

    To demonstrate the procedure described previously, we set an air-seawater-seafloor three-layer model, which is called model M0 (Fig.4a). The resistivity of the air, the seawater and the seafloor is set to be 1010Ωm, 0.3Ωm and 10Ωm, respectively, and the seawater depth is 500m.

    Assuming that a ship travels from1=?1250m to2= 1250m at a constant speed of 3ms?1, the EMFMS can be simulated by using two moving electric dipoles. The one is the alternating electric dipole with a frequency of 3.6Hz and the other is static electric dipole. Both the dipoles are located at the same place and the positive and negative electrodes are at the points (?25, 0, 3) and (+25, 0, 3), respectively. Both of them have a current of 20A. A receiver is positioned at point (0, 0, 500) on the seafloor. Both the frequency domain shaft-rate field (=3.6Hz) and steady field are calculated and shown in Figs.4b and 4c. Assuming that the centers of the dipole sources are equidistantly placed along the line from=?1250m to=1250m at a depth of 3m, the frequency domain shaft-rate fields are transformed into the time domain by using the discrete fast Fourier transform (iFFT), where the frequency interval Δis set to be 0.0012Hz and the number of sample points is equal to 213. The time domain shaft-rate fields at all 213points are obtained by using discrete iFFT (Press., 1992). Finally, the shaft-rate field at the receiver site is synthetized by extracting corresponding value from the 213data set and shown as the red lines in Figs.4d and 4e.

    Fig.4 The numerical example of the EMFMS. (a), Schematic diagram of model M0; (b), Frequency domain Ey component; (c), Hx component; (d), Time domain Ey component; (e), Hx component; (f), Ey component and (g) Hx component of EM- FMS.

    From Figs.4b–4e, one can see that the amplitude of the shaft-rate fields differs from the static field in both the frequency domain (Figs.4b and 4c) and the time domain (Figs.4d and 4e). This means that the EMFMS is different from either the shaft-rate EM field or the static field. Thus, both of them need to be simulated and investigated.

    3 Analysis of EMFMS

    The characteristics of EMFMS responses are related to several parameters in the model M0 shown in Fig.4a. In this section, the effects of both the source current intensity and source position on EMFMS are investigated, re- spectively.

    3.1 Source Current Intensity

    The current intensity of the shaft-rate field might be dif- ferent from that of the static field, thus there is a need to investigate their influences on the EMFMS, respectively.

    Firstly, we investigate the influence of the direct current intensity on the EMFMS. Assuming that the direct current intensities are 4A (model M1, Fig.5a) and 100A (model M2, Fig.5b), respectively, and the other parameters are the same as those in model M0 (Fig.4a), the simulated EMFMS for models M1 and M2 are shown in Figs.5c–5e.

    Fig.5 Schematic diagrams of (a) model M1 and (b) model M2 and the simulated results of (c) Ey, (d) Ez, and (e) Hx to illustrate the effects of direct current intensity on the EMFMS.

    From Figs.5c–5e, one can see that the EMFMS has the following features:

    1) The horizontal components of both the electric and magnetic fields (EandH) have a single peak in their variation curves and is symmetric with respect to the axis of=416.5s (Figs.5c and 5e), while the vertical component of the electric fieldEhas two peaks, one of which is positive at=334s and the other is negative at=499s (Fig.5d). The EMFMS attenuates faster and faster when the ship approaches to the receiver, but this trend slows down when it is far away from the receiver. The EMFMS envelope is crescent-shaped for models M0 and M2, but is spindle-shaped for model M1.

    2) The EMFMS’s amplitude increases with the increase of the direct current intensity, and the influence of direct current intensity on the magnetic field (H) is much greater than on the electric fields (EandE).

    Next, we investigate the influence of alternative current intensity on the EMFMS. We assume that the alternative current intensity is 4A (model M3, Fig.6a) and 100A (mo-del M4, Fig.6b), respectively, and the other parameters are the same as those in model M0 (Fig.4a). The simulated EMFMS for models M3 and M4 are shown in Figs.6c–6e.

    From Figs.6c–6e, one can see that the EMFMS has the following features:

    1) The peak’s position and symmetric feature of EM- FMS response in models M3 and M4 are similar to those in models M1 and M2.

    2) The range of the EMFMS envelope increases with the increase of the alternating current intensity.

    From Figs.5 and 6, one can see that the direct current intensity affects the peak’s position and symmetric feature of the EMFMS, while the alternating current intensity af- fects the range of the envelope.

    3.2 Source Position

    The alternating current source is not usually located at the same position as the direct current source. In the following, we discussed the influence of the source position on EMFMS.

    We assume that the alternating current source shifts 50 m horizontally from its position in model M0 (Fig.4a) along the positive and negative-axis direction, respectively, as shown in Fig.7a (model M5) and Fig.7b (model M6), and the other parameters are same as those in model M0 (Fig.4a). The simulated results of EMFMS for models M5 and M6 are shown in Figs.7c–7e.

    From Figs.7c–7e, one can see that the EMFMS is no longer symmetric with respect to the axis of=416.5s, this is because the symmetric centers of the shaft-rate field and the static field are at different position.

    Considering the shallow sea environments, we assume that the thickness of the seawater layer is 100m in models M7 and M8 (Figs.8a and 8b), and the other parameters are same as those in models M5 and M6. The simulated EMFMS for models M7 and M8 are shown in Figs.8c–8e.

    Fig.6 Schematic diagrams of (a) model M3 and (b) model M4 and the simulated results of (c) Ey, (d) Ez, and (e) Hx to illustrate the effects of alternating current intensity on the EMFMS.

    Fig.7 Schematic diagrams of (a) model M5 and (b) model M6 and the simulated results of (c) Ey, (d) Ez, and (e) Hx to illustrate the effects of the source position on the EM- FMS.

    By comparing Figs.7 and 8, one can find that when the seawater depth is much larger than the length of the current source, the source position has very little influence on the EMFMS, and vice versa. There are two reasons for this. One is that the shaft-rate field is of the same order in magnitude as the static field in shallow water. The other is the offsets of symmetric centers between the shaft-rate field and the static field are much larger in shallow water than in deep water.

    3.3 Combined Effect of HED and VED Sources

    In order to investigate the combined effect of HED and VED sources on EMFMS, we build the model M9 and M10. In model M9, there is a HED source, and both the alternating and static horizontal dipole sources are located at the same position and their positive and negative electrodes are at (?25, 0, 15) and (+25, 0, 15), respectively, as shown in Fig.9a. In model M10, the dipole source is tilted at an angle of 30? relative to the-axis and its center is at (, 0, 15), as shown in Fig.9b. The simulated EM- FMS of both models are shown in Figs.9c–9e.

    From Figs.9c–9e, one can see that for the tilted dipole source (model M10), the electric fields are no longer symmetrical with respect to the axis of=416.5s. The electrical field amplitude on the left side becomes smaller and that on the right side becomes larger, and the amplitude of the magnetic field is smaller than that due to the horizontal dipole source (model M9). It is obvious that these features are resulting from the combined effect of the HED and VED sources.

    Fig.8 Schematic diagrams of (a) model M7 and (b) model M8 and the simulated results of (c) Ey, (d) Ez, and (e) Hxto illustrate the effect of the source position on the EMFMS in shallow water.

    Fig.9 Schematic diagrams of (a) model M9 and (b) model M10 and the simulated results of (c) Ey, (d) Ez, and (e) Hxto illustrate the combined effect of HED and VED sources.

    4 Measured Data

    We conducted an EMFMS test in the South Yellow Sea. An ocean bottom EM receiver (OBEM) was positioned on the seabed and recorded three electric field components and two horizontal components of the magnetic field. The sampling rate is 500Hz, and the water depth is 37m.

    The research vessel ‘’ traveled across over the OBEM. The recorded data are processed. The shaft-rate of the vessel is about 3.667Hz.

    Figs.10a and 10b show the measuredEand Hfields during a period of 216s, respectively. The measured fields are divided into the shaft-rate field and static field by using the sliding window technique (Figs.10c and 10d).

    From Figs.10c and 10d, one can see the following features.

    1) The anomaly of the shaft-rate magnetic field is greater than the shaft-rate electric field (in SI unit).

    2) TheEcomponent and theHcomponent of the sta- tic field in Figs.10c and 10d are very similar to the static fields in Figs.4d and 4e.

    3) The amplitude of static magnetic field is much larger than that of the shaft-rate magnetic field.

    From the time-frequency spectrograms (Figs.10e and 10f), one can see the following features:

    1) The static electric field is dominated at a frequency very close to 0Hz and the shaft-rate field is very clear at the fundamental frequency of 3.67Hz and its harmonics.

    2) The amplitude of the static magnetic field is much larger than the shaft-rate magnetic field, which is generated by the metal material of the vessel.

    Fig.10 Time series of (a) Ey and (b) Hx for measured EMFMS, time series of (c) Ey and (d) Hx for shaft-rate EM field and static field and spectrogram of (e) Ey and (f) Hx for EMFMS.

    5 Conclusions

    In this paper, we present a simulation method of electric and magnetic fields of a moving ship (EMFMS), which consisted of both the shaft-rate field generated by alterna- ting electric currents and the static field excited by static electric current. Then we investigated the effects of the current intensity and the source positions on the EMFMS. The numerical simulation and real measured data show that the seafloor, the shaft-rate field and the static field all have great impacts on EMFMS, so none of them could be neglected for EMFMS study.

    Acknowledgements

    This study is supported by the Fundamental Research Funds for the Central Universities (No. 201861020) and the Wenhai Program of Qingdao National Laboratory for Marine Science and Technology (QNLM) (No. 2017WH ZZB0201). We thank Drs. Ying Liu, Yunju Wu, Jie Lu, and Baoqiang Zhang for helpful suggestions on formula derivation of shaft-rate EM fields and data processing. We also thank two anonymous reviewers for valuable comments on our manuscript.

    Bao, Z., Gong, S., Sun, J., and Li, J., 2011. Localization of a horizontal electric dipole source embedded in deep sea by using two vector-sensors., 23 (3): 53-57, DOI: 10.3969/j.issn.1009-3486.2011. 03.012 (in Chinese with English abstract).

    Cheng, R., Jiang, R., and Gong, S., 2016. Calculation method of vessels’ shaft rate electric field equivalent source magnitude., 38 (2): 138-143, DOI: 10.11887/j.cn.201602023 (in Chinese with Eng- lish abstract).

    Holmes, J., 2006.. Morgan & Claypool Publishers, London, 78pp.

    Holtham, P., Jeffrey, I., Brooking, B., and Richards, T., 1999. Electromagnetic signature modeling and reduction.. London, UK, 97-100.

    Jeffrey, I., and Brooking, B., 1999. A survey of new electromagnetic stealth technologies.. Biloxi, Mississippi, 1-7.

    Li, D., Chen, C., Liu, H., and Yang, S., 2012. Green function method for extrapolating of ship’s underwater static electric field., 24 (3): 1-6, DOI: 10.3969/j.issn.1009-3486.2012.03.001 (in Chinese with English abstract).

    Li, Y., and Li, G., 2016. Electromagnetic field expressions in the wavenumber domain from both the horizontal and vertical electric dipoles., 13 (4): 505-515, DOI: 10.1088/1742-2132/13/4/505.

    Liu, S., Xiao, C., and Gong, S., 2004. Electromagnetic field of DC electric dipole in two-layer model., 28 (5): 641-644, DOI: 10.3963/j.issn.2095-3844.2004.05. 004 (in Chinese with English abstract).

    Liu, Y., 2009. The measurement method of ship’s electric field. Master thesis. Harbin Engineering University (in Chinese with English abstract).

    Lu, X., Gong, S., Zhou, J., and Liu, S., 2005. Quasi-near field localization of a time-harmonic HED in sea water., 29 (3): 331-334, DOI: 10.3963/j.issn.2095-3844. 2005.03.001 (in Chinese with English abstract).

    Lu, X., Gong, S., Zhou, J., and Sun, M., 2004. Analytical expressions of the electromagnetic fields produced by an ELF time-harmonic HED embedded in the sea., 19 (3): 290-295, DOI: 10.13443/j.cjors.2004. 03.008 (in Chinese with English abstract).

    Nain, H., Isa, M. C., Mohd, M., Yusoff, N. H. N., Yati, M. S. D., and Nor, I. M., 2013. Management of naval vessel’s electromagnetic signatures: A review of sources and countermeasures., 6 (2): 93-110.

    Ni, H., Sun, M., and Gong, S., 2006. Calculation of the electromagnetic fields generated by horizontal current element in semi-infinite space of seawater., 20 (1): 63-65, DOI: 10.3969/j.issn. 1672-1497.2006.01.016 (in Chinese with English abstract).

    Press, W. H., Flannery, B. P., Teukolsky, S. A., and Vetterling, W. T., 1992.. Press Syndicate of the University of Cambridge, New York, 1574pp.

    Sun, M., Gong, S., Zhou, J., and Lu, X., 2003. Calculation of the electromagnetic fields generated by DC horizontal current element in semi-infinite space of seawater.. Istanbul, Turkey, 734-736.

    Zhang, J., and Wang, X., 2016. Arithetic research about electric- field intensity of horizontal-harmonic current in the deep sea., 38 (1): 90-93, DOI: 10.3404/j. issn.1672-7649.2016.1.019 (in Chinese with English abstract).

    Zolotarevskii, Y. M., Bulygin, F. V., Ponomarev, A. N., Narchev,V. A., and Berezina, L. V., 2005. Methods of measuring the low- frequency electric and magnetic fields of ships., 48 (11): 1140-1144, DOI: 10.1007/s11018-006- 0035-6.

    . E-mail: yuguo@ouc.edu.cn

    September 18, 2019;

    February 26, 2020;

    April 18, 2020

    (Edited by Chen Wenwen)

    av卡一久久| 99热这里只有精品一区| 亚洲人成网站在线播| 中国美白少妇内射xxxbb| 亚洲电影在线观看av| av播播在线观看一区| 亚洲国产欧美在线一区| 亚洲综合精品二区| 免费看日本二区| 欧美老熟妇乱子伦牲交| 国产黄色免费在线视频| 日韩av免费高清视频| 国产亚洲av嫩草精品影院| 久久久久久久久久久丰满| av在线亚洲专区| 国产爱豆传媒在线观看| 日韩制服骚丝袜av| 性插视频无遮挡在线免费观看| 欧美 日韩 精品 国产| 中文资源天堂在线| av在线观看视频网站免费| 亚洲国产欧美在线一区| 热99国产精品久久久久久7| 亚洲精品一区蜜桃| 免费av不卡在线播放| 精品久久久久久久久亚洲| 18禁在线播放成人免费| 成年免费大片在线观看| 亚洲在久久综合| 黄片无遮挡物在线观看| 国产国拍精品亚洲av在线观看| 久久综合国产亚洲精品| 亚洲av电影在线观看一区二区三区 | 五月伊人婷婷丁香| 亚洲自拍偷在线| 日韩av不卡免费在线播放| 国产一区二区三区av在线| 亚洲美女视频黄频| 啦啦啦在线观看免费高清www| 欧美成人a在线观看| 国产精品久久久久久精品电影小说 | 男女下面进入的视频免费午夜| 少妇丰满av| av免费在线看不卡| 国产欧美另类精品又又久久亚洲欧美| 精品一区在线观看国产| 亚洲色图综合在线观看| 中文字幕免费在线视频6| 成人高潮视频无遮挡免费网站| 国产黄频视频在线观看| 色视频在线一区二区三区| 成人二区视频| 99久久九九国产精品国产免费| 哪个播放器可以免费观看大片| 偷拍熟女少妇极品色| 三级国产精品片| 欧美日本视频| 欧美日韩视频精品一区| 在线观看美女被高潮喷水网站| 成年免费大片在线观看| 伦精品一区二区三区| 国产精品福利在线免费观看| 午夜免费鲁丝| 在线亚洲精品国产二区图片欧美 | 一本久久精品| 国产日韩欧美在线精品| av网站免费在线观看视频| 久久人人爽人人爽人人片va| 熟女人妻精品中文字幕| 亚洲精华国产精华液的使用体验| 国产精品无大码| 综合色丁香网| 国产欧美日韩一区二区三区在线 | 卡戴珊不雅视频在线播放| 欧美成人a在线观看| 国产精品人妻久久久影院| 国产探花在线观看一区二区| 久热久热在线精品观看| 亚洲欧美精品自产自拍| av免费在线看不卡| 七月丁香在线播放| 婷婷色综合www| 三级国产精品欧美在线观看| 波多野结衣巨乳人妻| 欧美高清成人免费视频www| 神马国产精品三级电影在线观看| 欧美高清性xxxxhd video| 97超视频在线观看视频| 97超碰精品成人国产| 看非洲黑人一级黄片| 亚洲高清免费不卡视频| 国产成人精品福利久久| 国产免费视频播放在线视频| 国产欧美亚洲国产| 亚洲婷婷狠狠爱综合网| 一区二区三区精品91| 欧美一级a爱片免费观看看| 成人二区视频| 国产大屁股一区二区在线视频| 国产探花在线观看一区二区| 国产精品国产av在线观看| 久久久久国产网址| 亚洲欧美日韩东京热| 18+在线观看网站| 极品少妇高潮喷水抽搐| 国精品久久久久久国模美| 亚洲精品影视一区二区三区av| 身体一侧抽搐| 欧美高清成人免费视频www| 五月天丁香电影| 又大又黄又爽视频免费| 国产淫语在线视频| 国产精品久久久久久av不卡| av线在线观看网站| 国产亚洲精品久久久com| 禁无遮挡网站| 一区二区av电影网| 小蜜桃在线观看免费完整版高清| 国产精品嫩草影院av在线观看| 少妇被粗大猛烈的视频| 白带黄色成豆腐渣| 又爽又黄无遮挡网站| 日韩精品有码人妻一区| 国产伦在线观看视频一区| 香蕉精品网在线| 一二三四中文在线观看免费高清| 亚洲欧洲国产日韩| 人人妻人人澡人人爽人人夜夜| 九九爱精品视频在线观看| 国产亚洲精品久久久com| 亚洲精品国产色婷婷电影| 亚洲av国产av综合av卡| 国产伦在线观看视频一区| 免费黄网站久久成人精品| 成人亚洲精品av一区二区| 涩涩av久久男人的天堂| 伦精品一区二区三区| av网站免费在线观看视频| 成人国产麻豆网| 自拍欧美九色日韩亚洲蝌蚪91 | 亚洲国产最新在线播放| 99久久中文字幕三级久久日本| 成年版毛片免费区| 91久久精品电影网| 亚洲综合色惰| 最近中文字幕高清免费大全6| 熟女人妻精品中文字幕| 在线观看人妻少妇| 精品酒店卫生间| 国产精品偷伦视频观看了| 九色成人免费人妻av| 性插视频无遮挡在线免费观看| 三级国产精品片| 午夜视频国产福利| 不卡视频在线观看欧美| 黄色日韩在线| 纵有疾风起免费观看全集完整版| 亚洲欧美日韩无卡精品| 亚洲国产欧美在线一区| 丝袜美腿在线中文| 久久精品夜色国产| 乱码一卡2卡4卡精品| 亚洲在久久综合| 久久热精品热| 少妇丰满av| 狂野欧美激情性xxxx在线观看| 国语对白做爰xxxⅹ性视频网站| 韩国高清视频一区二区三区| 国产探花在线观看一区二区| 精品少妇黑人巨大在线播放| 免费电影在线观看免费观看| 免费在线观看成人毛片| 免费av不卡在线播放| 在线观看三级黄色| 18禁动态无遮挡网站| 亚洲电影在线观看av| 日本猛色少妇xxxxx猛交久久| 又爽又黄无遮挡网站| 大陆偷拍与自拍| 国产国拍精品亚洲av在线观看| 青春草国产在线视频| 大香蕉久久网| 国产成人福利小说| 国产久久久一区二区三区| 午夜福利在线观看免费完整高清在| 久久久久久国产a免费观看| 欧美 日韩 精品 国产| 看十八女毛片水多多多| 国产精品国产三级国产av玫瑰| 国产成人aa在线观看| 亚洲在久久综合| 97超视频在线观看视频| 麻豆乱淫一区二区| 国产又色又爽无遮挡免| 肉色欧美久久久久久久蜜桃 | 亚洲精品国产色婷婷电影| 日韩av不卡免费在线播放| 极品少妇高潮喷水抽搐| 麻豆成人午夜福利视频| 狂野欧美激情性xxxx在线观看| av网站免费在线观看视频| 日韩成人伦理影院| 国产久久久一区二区三区| 欧美zozozo另类| xxx大片免费视频| 69av精品久久久久久| 日韩欧美精品免费久久| 色婷婷久久久亚洲欧美| 美女视频免费永久观看网站| 在线观看人妻少妇| www.av在线官网国产| 午夜福利在线在线| 丰满人妻一区二区三区视频av| 色吧在线观看| 国产免费视频播放在线视频| 亚洲精品成人av观看孕妇| av在线app专区| 国产探花极品一区二区| 神马国产精品三级电影在线观看| 五月玫瑰六月丁香| 晚上一个人看的免费电影| 免费观看在线日韩| 啦啦啦中文免费视频观看日本| 日本一本二区三区精品| 欧美日韩精品成人综合77777| 热99国产精品久久久久久7| 亚洲国产精品999| 久久久成人免费电影| 亚洲欧美日韩另类电影网站 | 麻豆久久精品国产亚洲av| 在线观看美女被高潮喷水网站| 国产大屁股一区二区在线视频| 一区二区三区精品91| 一级毛片我不卡| 免费av观看视频| 久久久成人免费电影| 国产精品国产三级国产专区5o| 久久久久久久久久人人人人人人| 久久人人爽av亚洲精品天堂 | 欧美区成人在线视频| 亚洲精品国产成人久久av| 亚洲美女搞黄在线观看| av网站免费在线观看视频| 性插视频无遮挡在线免费观看| 久久久欧美国产精品| 高清日韩中文字幕在线| 少妇熟女欧美另类| 交换朋友夫妻互换小说| 少妇猛男粗大的猛烈进出视频 | 欧美国产精品一级二级三级 | 久久人人爽av亚洲精品天堂 | 熟女av电影| 国产精品久久久久久精品电影| 日本黄色片子视频| 身体一侧抽搐| 国语对白做爰xxxⅹ性视频网站| 久久久久久久久久成人| 亚洲最大成人av| 新久久久久国产一级毛片| 精品人妻视频免费看| 在现免费观看毛片| 国产毛片a区久久久久| av一本久久久久| 又爽又黄a免费视频| 亚洲欧美日韩无卡精品| 青春草国产在线视频| 麻豆久久精品国产亚洲av| 六月丁香七月| 精品酒店卫生间| 青春草亚洲视频在线观看| 日本一本二区三区精品| 七月丁香在线播放| 国产久久久一区二区三区| 亚洲自拍偷在线| 人妻少妇偷人精品九色| 国产精品久久久久久久电影| 欧美成人一区二区免费高清观看| 白带黄色成豆腐渣| 女人十人毛片免费观看3o分钟| 亚洲av中文字字幕乱码综合| av又黄又爽大尺度在线免费看| 亚洲av不卡在线观看| 中文字幕av成人在线电影| 欧美成人一区二区免费高清观看| 国产在线男女| 国产一区二区在线观看日韩| 王馨瑶露胸无遮挡在线观看| 欧美潮喷喷水| 免费av毛片视频| 黄色日韩在线| 中文资源天堂在线| 亚洲怡红院男人天堂| 大码成人一级视频| 亚洲欧美日韩另类电影网站 | 极品教师在线视频| 最近中文字幕2019免费版| 久久精品综合一区二区三区| 少妇熟女欧美另类| 亚洲无线观看免费| 蜜桃亚洲精品一区二区三区| 国产精品麻豆人妻色哟哟久久| 超碰97精品在线观看| 九九在线视频观看精品| 成人国产av品久久久| 在现免费观看毛片| 天堂网av新在线| 亚洲精品aⅴ在线观看| 午夜亚洲福利在线播放| 精品久久久噜噜| 成人国产麻豆网| av女优亚洲男人天堂| 夜夜爽夜夜爽视频| 国产午夜福利久久久久久| 久久久国产一区二区| 久久精品夜色国产| 国产伦理片在线播放av一区| 最新中文字幕久久久久| 高清欧美精品videossex| 免费少妇av软件| 91午夜精品亚洲一区二区三区| 亚洲精品国产成人久久av| 青春草视频在线免费观看| 99久久精品热视频| 欧美高清性xxxxhd video| 亚洲精品成人久久久久久| 99热6这里只有精品| 国产免费一级a男人的天堂| 丰满少妇做爰视频| 你懂的网址亚洲精品在线观看| 国产免费视频播放在线视频| 看十八女毛片水多多多| 亚洲,一卡二卡三卡| 亚洲无线观看免费| 综合色丁香网| 国产伦在线观看视频一区| 我要看日韩黄色一级片| av在线亚洲专区| 欧美国产精品一级二级三级 | 高清在线视频一区二区三区| 亚洲av.av天堂| 亚洲美女搞黄在线观看| 又大又黄又爽视频免费| 亚洲图色成人| 久久久成人免费电影| 蜜桃久久精品国产亚洲av| 亚洲精品日韩av片在线观看| 欧美日韩亚洲高清精品| 少妇被粗大猛烈的视频| 精品99又大又爽又粗少妇毛片| 亚洲自拍偷在线| 日本黄色片子视频| 日本午夜av视频| 啦啦啦啦在线视频资源| 欧美日韩在线观看h| 秋霞在线观看毛片| av播播在线观看一区| 亚洲精品成人av观看孕妇| 男女边摸边吃奶| 亚洲成人久久爱视频| av在线蜜桃| 高清日韩中文字幕在线| 中文字幕免费在线视频6| 成人黄色视频免费在线看| 男人狂女人下面高潮的视频| 看非洲黑人一级黄片| 在线亚洲精品国产二区图片欧美 | 国产色爽女视频免费观看| 国产伦精品一区二区三区视频9| 欧美极品一区二区三区四区| 日韩精品有码人妻一区| 新久久久久国产一级毛片| 久久久久久伊人网av| 国产大屁股一区二区在线视频| av免费在线看不卡| 国产色婷婷99| 国产精品三级大全| 国产又色又爽无遮挡免| 综合色丁香网| 日韩国内少妇激情av| 欧美日韩视频高清一区二区三区二| 日韩成人伦理影院| 一区二区三区四区激情视频| .国产精品久久| 欧美日韩国产mv在线观看视频 | 亚洲自偷自拍三级| 日韩一区二区视频免费看| 久久精品综合一区二区三区| 色5月婷婷丁香| 色视频在线一区二区三区| 国产成人freesex在线| 天美传媒精品一区二区| 看十八女毛片水多多多| 午夜福利视频1000在线观看| av在线蜜桃| 精品人妻熟女av久视频| 亚洲精品日韩在线中文字幕| 国产一级毛片在线| 99久久精品热视频| 午夜精品一区二区三区免费看| xxx大片免费视频| 免费人成在线观看视频色| 国产国拍精品亚洲av在线观看| 国产伦精品一区二区三区四那| 男女国产视频网站| 91狼人影院| 91在线精品国自产拍蜜月| 99久久九九国产精品国产免费| 大片免费播放器 马上看| 99视频精品全部免费 在线| 一本久久精品| 国产精品一区二区性色av| 国产成人aa在线观看| 国产极品天堂在线| 亚洲精品456在线播放app| 日本午夜av视频| 亚洲不卡免费看| 亚洲国产av新网站| 成人综合一区亚洲| 青春草亚洲视频在线观看| 不卡视频在线观看欧美| 欧美成人一区二区免费高清观看| 三级国产精品欧美在线观看| 日韩一区二区三区影片| 亚洲欧美日韩无卡精品| 久久精品国产鲁丝片午夜精品| 久久久久久久久大av| 97在线人人人人妻| 一区二区av电影网| 欧美xxxx性猛交bbbb| 丰满少妇做爰视频| 亚洲丝袜综合中文字幕| 中文天堂在线官网| 亚洲av电影在线观看一区二区三区 | 有码 亚洲区| 热re99久久精品国产66热6| 在线播放无遮挡| 免费看a级黄色片| 深爱激情五月婷婷| 欧美 日韩 精品 国产| 亚洲国产日韩一区二区| 亚洲伊人久久精品综合| 春色校园在线视频观看| 国产高清三级在线| 欧美xxⅹ黑人| 亚洲内射少妇av| 简卡轻食公司| 久久精品国产亚洲av涩爱| 看非洲黑人一级黄片| 日本一二三区视频观看| 精品久久久久久久人妻蜜臀av| av在线观看视频网站免费| 99九九线精品视频在线观看视频| 日韩一区二区三区影片| 免费大片黄手机在线观看| 99久久中文字幕三级久久日本| 国产成人aa在线观看| 久久久久久九九精品二区国产| 亚洲精品久久午夜乱码| 精品人妻一区二区三区麻豆| www.av在线官网国产| 久久精品国产自在天天线| 久久人人爽人人片av| 亚洲成人av在线免费| 舔av片在线| 18禁动态无遮挡网站| 寂寞人妻少妇视频99o| 91久久精品国产一区二区三区| 亚洲精品中文字幕在线视频 | 国产午夜精品久久久久久一区二区三区| 激情 狠狠 欧美| 久久精品国产亚洲网站| kizo精华| 自拍偷自拍亚洲精品老妇| 下体分泌物呈黄色| 国产精品麻豆人妻色哟哟久久| 日韩制服骚丝袜av| 黄色视频在线播放观看不卡| 波多野结衣巨乳人妻| 欧美精品国产亚洲| 久久久久久久亚洲中文字幕| 97超视频在线观看视频| 国产高清三级在线| av又黄又爽大尺度在线免费看| 乱系列少妇在线播放| 国产午夜精品一二区理论片| 少妇人妻久久综合中文| 亚洲国产精品成人久久小说| 久久久久久久久久成人| 久久久久精品久久久久真实原创| 97热精品久久久久久| 网址你懂的国产日韩在线| 天天躁日日操中文字幕| 免费大片黄手机在线观看| 美女xxoo啪啪120秒动态图| 国产精品国产av在线观看| av又黄又爽大尺度在线免费看| 中文在线观看免费www的网站| 26uuu在线亚洲综合色| 女人被狂操c到高潮| 亚洲av中文av极速乱| 亚洲国产色片| 国产女主播在线喷水免费视频网站| 99久久精品国产国产毛片| 欧美最新免费一区二区三区| av卡一久久| 国产毛片a区久久久久| 国产黄片视频在线免费观看| 国产一区二区三区综合在线观看 | 国产极品天堂在线| 国产视频内射| 国产精品无大码| 啦啦啦啦在线视频资源| 亚洲欧美日韩无卡精品| 一级av片app| 午夜福利高清视频| 水蜜桃什么品种好| 3wmmmm亚洲av在线观看| 联通29元200g的流量卡| 日韩成人av中文字幕在线观看| 夜夜看夜夜爽夜夜摸| 青春草国产在线视频| 99热网站在线观看| 亚洲精品一二三| 毛片一级片免费看久久久久| 日韩av不卡免费在线播放| 内地一区二区视频在线| 日本猛色少妇xxxxx猛交久久| 看免费成人av毛片| 男人和女人高潮做爰伦理| 国产一区二区三区av在线| 国产日韩欧美亚洲二区| 18禁在线播放成人免费| 亚洲国产高清在线一区二区三| 美女高潮的动态| 亚洲av男天堂| 亚洲精品一二三| 国语对白做爰xxxⅹ性视频网站| 免费高清在线观看视频在线观看| 乱码一卡2卡4卡精品| 国产精品精品国产色婷婷| 国产熟女欧美一区二区| a级毛色黄片| 亚洲国产精品专区欧美| 久久久欧美国产精品| av国产久精品久网站免费入址| 久久久亚洲精品成人影院| 别揉我奶头 嗯啊视频| 亚洲精品国产成人久久av| 国产男女超爽视频在线观看| 麻豆精品久久久久久蜜桃| 中国三级夫妇交换| 日韩国内少妇激情av| 精品一区二区三区视频在线| 又大又黄又爽视频免费| 另类亚洲欧美激情| 亚洲综合精品二区| 深夜a级毛片| 亚洲人成网站高清观看| 综合色丁香网| 永久免费av网站大全| 亚洲人成网站在线播| 日本猛色少妇xxxxx猛交久久| 久久久久久久久久久免费av| 少妇熟女欧美另类| 免费不卡的大黄色大毛片视频在线观看| 尾随美女入室| 一本一本综合久久| 99热国产这里只有精品6| 80岁老熟妇乱子伦牲交| 一区二区三区乱码不卡18| 国产精品无大码| 联通29元200g的流量卡| 性插视频无遮挡在线免费观看| 日日啪夜夜撸| 又黄又爽又刺激的免费视频.| 亚洲av一区综合| 两个人的视频大全免费| 久久精品国产亚洲av天美| av一本久久久久| 在线天堂最新版资源| 91精品国产九色| 久久久久久国产a免费观看| 欧美日韩综合久久久久久| 干丝袜人妻中文字幕| 五月玫瑰六月丁香| 三级经典国产精品| 一级黄片播放器| 一级毛片 在线播放| 国产成人freesex在线| 久久久久九九精品影院| 日韩一本色道免费dvd| 久久99热6这里只有精品| 亚洲电影在线观看av| 久久国产乱子免费精品| 国产一级毛片在线| 亚洲伊人久久精品综合| av在线app专区| 亚洲精品国产成人久久av| 精品少妇黑人巨大在线播放| 国产免费一区二区三区四区乱码| 亚洲欧美一区二区三区黑人 | 国产高潮美女av| 最近的中文字幕免费完整| 五月伊人婷婷丁香| 国产成人a区在线观看| 精品久久久久久久久av| 麻豆成人av视频| av卡一久久| 男女啪啪激烈高潮av片| 国产69精品久久久久777片| 亚洲精品,欧美精品| 中文在线观看免费www的网站| 搡老乐熟女国产| www.av在线官网国产| 国产老妇伦熟女老妇高清|