| 摘要: |
| 将海底沉积物视为一种松散的湿颗粒介质，并假设海水与沉积物的界面是平的，由位移、动量密度及压强在界面处的连续性，导出平面声波在其上的反射系数，建立反射系数与沉积物的具体参数的联系。所得结果可化为前人用唯象理论所获得的形式。将理论与实验比较的结果表明，两者的一致性是好的。 |
| 关键词: 湿颗粒介质 声波 反射系数 |
| DOI： |
| 分类号: |
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附件 |
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| REFLECTION OF ACOUSTIC WAVES FROM LOOSE MARINE SEDIMENT |
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Tang Yingwu
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Institute of Bei Hai, Academia Sinica, Qingdao 266023
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| Abstract: |
| In this paper, the marine sediment is regarded as wet loose granular medium where the propagation of sound can excite a dilatation wave but not a rotating wave, and the seawater-sediment interface is assumed to be a plane. The reflection coefficient V at sediment surface is derived as
(For the equations please see the PDF file.)
where k0 is the wave number of the sea water, k1 the wave number of the sediment, ω the angular frequency, ρ0 the density of the sea water, q the porosity of the sediment, α0 the grazing angle in sea water, α1 the grazing angle in sediment,
B0 = q/[(q/B1) + (1-q)/ B2], B1 and B2 are the bulk modulus of the pore water and the sediment grains, respectively.
Thus, the connection of the derived reflection coefficient with various parameters in sediment is established. The obtained result is identical with that obtained by phenomenon theory and agrees well with practical data. |
| Key words: Wet granular media, Acoustic wave, Reflection coefficient |
