海岸湿沙表面风沙传输特征的风洞实验研究

摘要/Abstract

摘要：

通过湿沙表面风沙传输的风洞实验,研究了湿润海岸风沙流的垂直结构、输沙率随风速与表层湿度的变化规律。输沙测量使用60 cm高直立式积沙仪,湿度（M）为沙面表层1 mm厚的重量湿度值。结果表明,湿沙表面的输沙量和高度呈指数关系。一般,湿度增大,整体输沙率降低,高湿度床面的沙粒有相对更大的比例被传输到更高的位置。比起低湿度（M＜0.587%）沙粒,高湿度（0.587%＜M＜1.448%）沙粒的垂直运动对湿度变化的影响更加敏感,尤其是在跃移层的底部,当M＞1.448%时,输沙率已经很低,小于0.99 g·cm-1·s-1。伴随湿度0.587%和1.448%的过渡,风沙流垂向分布被分为3个不同坡度的区域,曲线坡度反映了沙粒间不同水分存在形式的影响差异。对于跃移沙粒,高湿度表面（M＞1.448%）仅起到了一个传输平台的作用;当表面变干到某种程度（M=0.587%）之前,表面湿度是跃移运动的主要控制因子,然后风速才重新开始影响输沙。

关键词: 风沙流, 湿度, 湿沙, 垂向分布, 输沙率, 海岸, 风洞

Abstract:

The change characters of wind-sand flow structure and sand transport rate under different wind speed and different moisture coast were studied in wind tunnel experiments. In the experiment, a standard 60-cm height vertical sand trap was used, and the moisture content was gravimetric moisture content of surface sand within 1-mm thick. Results show that the sand transport profile over the wet surface can be expressed with an exponential equation. Generally, the influence of moisture content on sand transport profile mainly focuses on the bottom of the blowing sand cloud. Meanwhile, the total sand transport drops with the increase of moisture content, and a relatively larger proportion is transported at greater height. The vertical movement of particles over higher moisture surface (0.587%＜M＜1.448%) is more sensitive to moisture content variation as compared to those over lower wet surface (M＜0.587%), especially, the total sand transport rate tends to be rather low (0.99 g·cm-1·s-1) when M＞1.448%. The profile of the total sand transport rate varying with moisture content can be divided into three different gradient regions. The gradient of the curve reflects the different influences of the water regime in surface sediments. The higher moisture surface (M＞1.448%) merely functions as a transport plain for the saltation particles. Surface moisture content is the dominant control factor for saltation activity when the moisture content is in 0.587%-1.448%, and wind velocity will control saltation after the surface dries to the extent of M<0.587%.

Key words: wind-sand flow, moisture content, wet sand, flux profile, sand transport rate, coast, wind tunnel experiment

中图分类号:

X169

韩庆杰1,2, 屈建军1,2, 廖空太3, 朱淑娟4, 董治宝1, 张克存1, 俎瑞平1. 海岸湿沙表面风沙传输特征的风洞实验研究[J]. 中国沙漠, 2012, 32(6): 1512-1521.

参考文献

[1]Bauer B O,Davidson-Arnott R G D. A general framework for modelling sediment supply to coastal dunes including wind angle,beach geometry,and fetch effects[J].Geomorphology,2002,49:89-108.

[2]Nickling W G,Davidson-Arnott R G D.Aeolian sediment transport on beaches and coastal sand dunes[M]//Davidson-Arnott,R G D.Proceedings Symposium on Coastal Sand Dunes.National Research Council of Canada,1990:1-35.

[3]Horikawa K,Hotta S,Kubota S,et al.Blown sand on beaches[M].Proceeding of The 28th Japanese Conference on Coastal Engineering,1981:574-578.

[4]Horikawa K,Hotta S,Kubota S.Experimental study of blown sand on a wetted sand surface[J].Coastal Engineering in Japan,1982,25:177-195.

[5]Neuman C M,Scott M M.A wind tunnel study of the influence of pore water on aeolian sediment transport[J].Journal of Arid Environments,1998,39(3):403-419.

[6]Sherman D J,Jackson D W T,Namikas S L,et al.Wind-blown sand on beaches:an evaluation of models[J].Geomorphology,1998,22:113-133.

[7]Van Dijk P M,Stroosnijder L.The influence of rainfall on transport of beach sand by wind[J].Earth Surface Processes and Landforms,1996,21:341-352.

[8]Sarre R.Evaluation of aeolian sand transport equations using intertidal zone measurements,Saunton Sands,England[J].Sedimentology,1988,35:671-679.

[9]Bauer B O,Sherman D J,Nordstrom K F,et al.Aeolian transport measurement and prediction across a beach and dune at Castroville,California[M]//Nordstrom K F,Psuty N P,Carter R W G.Coastal Dunes:Form and Process.Chichester:John Wiley,1990:39-55.

[10]Kroon A,Hoekstra P.Eolian sediment transport on a natural beach[J].Journal of Coastal Research,1990,6:367-380.

[11]Wal A,McManus J.Wind regime and sand transport on a coastal beach-dune complex,Tentsmuir,eastern Scotland[M]//Pye K.The Dynamics and Environmental Context of Aeolian Sedimentary Systems.Geological Society Special Publication No.72.London:The Geological Society,1993:159-172.

[12]Dong Z B,Liu X P,Wang H T.The flux profile of a blowing sand cloud:A wind tunnel investigation[J].Geomorphology,2003,49:219-230.

[13]Butterfield G R.Near-bed Mass flux profiles in Aeolian sand transport:High-resolution measurements in a wind tunnel[J].Earth Surface Processes and Landforms,1999,24:393-412.

[14]Dong Z B,Qian G Q.Characterizing the height profile of the flux of wind-eroded sediment[J].Environment Geology,2007,51:835-845.

[15]任春勇,武生智.沙源供给条件对风沙流结构的影响[J].中国沙漠,2011,31(3):597-601.

[16]张伟民,汪万福,张克存,等.不同沙源供给条件下砾石床面的风沙流结构与蚀积量变化风洞实验研究[J].中国沙漠,2009,29(6):1015-1020.

[17]武建军,罗生虎,闫光虎,等.脉动风场下风沙流结构的数值模拟[J].中国沙漠,2011,31(3):602-605.

[18]董玉祥,马骏.风速对海岸沙丘表面风沙流结构影响的实证研究[J].干旱区资源与环境,2009,23(9):179-183.

[19]蒋富强,李荧,李凯崇,等.兰新铁路百里风区风沙流结构特性研究[J].铁道学报,2010,32(3):105-110.

[20]Folk R L,Ward W C.A study in the significance of grain size parameters[J].Journal Sedimentary Petrology,1957,27:3-27.

[21]Reginato R J.Sampling soil-water distribution in the surface centimetre of a field soil[J].Soil Science,1975,120:292-294.

[22]Han Q J,Qu J J,Zhang K C,et al.Wind tunnel investigation of the influence of surface moisture content on the entrainment and erosion of beach sand by wind using sands from tropical humid coastal southern China[J].Geomorphology,2009,104:230-237.

[23]尹永顺.砾漠大风地区风沙流研究[J].中国沙漠,1989,9（4）:27-36.

[24]Dong Z B,Wang H T,Liu X P,et al.A wind tunnel investigation of the influence of fetch length on the flux profile of a sand cloud blowing over a gravel surface[J].Earth Surface Processes and Landforms,2004,13:1613-1626.

[25]Jensen J L,Rasmussen K R,Srensen M,et al.The Hanstholm experiment 1982.Sand grain saltation on a beach[R].Denmark:Department of Theoretical Statistics,Institute of Mathematics,University of Aarhus,1984:125.

[26]Butterfield G R.Grain transport rates in steady and unsteady turbulent airflows[J].Acta Mechanica,1991,1(Suppl.):97-122.

[27]Greeley R,Blumberg D G,Williams S H.Field measurements of the flux and speed of wind-blown sand[J].Sedimentology,1996,43:41-52.

[28]White B R,Mounla H.An experimental study of Froude number effect on wind-tunnel saltation[J].Acta Mechanica,1991,1(Suppl.):145-157.

[29]Rasmussen K R,Mikkelsen H E.On the efficiency of vertical array aeolian field traps[J].Sedimentology,1998,45:789-800.

[30]Nickling W G,Neuman C M.Wind tunnel evaluation of a wedgeshaped aeolian sediment trap[J].Geomorphology,1997,18:333-345.

[31]Bagnold R A.The Physics of Blown Sand and Desert Dunes[M].London:Methuen,1941:265.

[32]Anderson R S,Haff P K.Simulation of eolian saltation[J].Science,1988:241,820-823.

[33]McKenna N C,Nickling W G.Momentum extraction with saltation:implications for experimental evaluation of wind profile parameters[J].Boundary-Layer Meteorology,1994,68:35-50.

[34]Stout J E,Zobeck T M.The Wolfforth field experiment:a wind erosion study[J].Soil Science,1996,161:616-632.

[35]Horikawa K,Shen H W.Sand movement by wind action (On the characteristics of sand traps)[R].US Army Corps of Engineers,Beach Erosion Board,Technical Memorandum No.119.1960:51.

[36]Gillette D A,Stockton P H.The effect of nonerodible particles on wind erosion of erodible surfaces[J].Journal of Geophysical Research,1989,94:12885-12893.

[37]Stockton P,Gillette D A.Field measurement of the sheltering effect of vegetation on erodible land surfaces[J].Land Degradation and Rehabilitation,1990,2:77-85.

[38]Spaan W P,van den Abeele G D.Wind borne particle measurements with acoustic sensors[J].Soil Technology,1991,4(1):51-63.

[39]Williams G.Some aspects of the eolian saltation load[J].Sedimentology 1964,3,257-287.

[40]White B R.Two-phase measurements of saltating turbulent boundary layer flow[J].International Journal of Multiphase Flow,1982,8:459-473.

[41]Srensen M.Estimation of some aeolian saltation transport parameters from transport rate profiles[M]//Barndorff-Nielsen O E,M ller J T,Rasmussen K R,et al.International Workshop on the Physics of Blown Sand.Denmark:Aarhus University,1985:141-190.

[42]Sharp R P.Wind-driven sand in Coachella Valley,California[J].Geological Society of America Bulletin,1964,75:785-804.

[43]Nickling W G.Grain-size characteristics of sediment transported during dust storms[J].Journal of Sedimentary Petrology,1983,53:1011-1024.

[44]Rasmussen K R,S rensen M,Willetts B B.Measurements of saltation and wind strength on beaches[M]//Barndorff-Nielsen O E,Mller J T,Rasmussen K R,et al.Proceedings of International Workshop on the Physics of Blown Sand.Denmark:Aarhus University,1985:301-325.

[45]Anderson R S.Eolian sediment transport as a stochastic process:the effects of a fluctuating wind on particle trajectories[J].Journal of Geology,1987,95:497-512.

[46]Lancaster N.Geomorphology of Desert Dunes[M].London:Routledge,1995:211-214.

[47]Dong Z B,Wang H T,Liu X P,et al.Velocity profile of a sand cloud blowing over a gravel surface[J].Geomorphology,2002,45:277-289.

[48]McEwan I K,Willetts B B,Rice M A.The grain/bed collision in sand transport by wind[J].Sedimentology,1992,39:971-981.

[49]Wiggs G F S,Baird A J,Atherton R J.The dynamic effect of moisture on the entrainment and transport of sand by wind[J].Geomorphology,2004,59:15-30.

[50]Van Dijk P M,Stroosnijder L.The influence of rainfall on transport of beach sand by wind[J].Earth Surface Processes and Landforms,1996,21:341-352.

[51]Chepil W S.Influence of soil moisture on erodibility of soil by wind[J].Soil Science Society of America Proceedings,1956,20:288-292.

[52]Cornelis W M,Gabriels D,Hartmann R.A conceptual model to predict the deflation threshold shear velocity as affected by near-surface soil water:1.Theory[J].Soil Science Society of America,2004,68:1154-1161.

[53]Neuman C M,Nickling W G.A theoretical and wind tunnel investigation of the effect of capillary water on the entrainment of sediment by wind[J].Canadian Journal of Soil Science,1989,69:79-96.

[54]Baver L D.Soil Physics[M].New York:John Wiley and Sons,1948:252.

[55]Bisal F,Hsieh J.Influence of soil moisture on erodibility of soil by wind[J].Soil Science,1966,102:143-146.

[56]Cornelis W M,Gabriels D.The effect of surface moisture on the entrainment of dune sand by wind:an evaluation of selected models[J].Sedimentology,2003,50:771-790.