本文重點在於研究由波泥交互作用所造成之表面波衰減，在特定之實驗條件下，甚至只需數個表面波長與底床泥質之作用，即可造成表面波相當劇烈之衰減。當表面波通過泥質底床時，泥質流體的動力回應是造成波浪衰減的主要機制。影響能量衰減的參數有:波高、週期、水深與泥質的流變特性，本文將會於實驗研究上述之影響因子和波浪衰減機制之關係。
本實驗利用高嶺土水溶液當作泥質底床之材料，且此物之流變特性已由流變儀測之，且於各個試次間搭配不同之泥質密度與造波特性。接著，本試驗規劃的實驗儀器有:沿著人工底床架設的電容式波高計可量測表面波之衰減、固定擺放位置的兩台CCD照相機來觀測泥水交界面波之震盪與設計一可垂直位移之電磁式流速儀以便測量水槽中之水平與垂直之流速分佈。
由本次實驗的結果顯示能量衰減的原因不但與波長和泥質之流變性質有關，甚至與波浪尖銳度有高度密切之相關特性。基於無因次化參數與實驗的數據分析比較可得，吾人利用增加波能的概念式以修正波浪衰減的理論式，且此新理論式與實驗計算之結果有良好的比對。另外，本實驗進一步量測到泥質流體中存在邊界層與相位延遲之現象。

The paper focus on the attenuation of surface wave caused by the interactions between mud and wave.The damping of the surface wave can be considerable after only a few wavelengths.When surface wave propagates over the mud beds, the dynamic respone of fluild mud is main mechanism for damping. Several parameters have influence on energy dissipation, including wave height, wave period, water depth and rheology properties of mud. These factors will be experimentally investigated and damping mechanism is presented in this paper.
The mixture Kaolin with water was selected as fluid mud in the experiment and the rheology property was test by rheometer. Different levels of mud density, wave heights and wave periods are tested. Capacitance-type wave gages were used to measure surface wave heights attenuation along the trench, and two CCD cameras were used to monitor interface elevation at fixed position. The electromagnetic current meter (EMC) is applied to measure horizontal and vertical velocity distribution in the vertical column.
The results reveal that energy dissipation depends not only on wave length and rheology of mud, but also highly depends on wave steepness. Base on non-dimensional parameter and experimental data, we modify the damping theory by adding conceptual energy. The new formula agree fairly with experimental data. Furthermore, the induced boundary layer thickness and phase difference in the fluid mud was presented.

1.Chiu-On Ng, Water waves over a muddy bed: a two-layer Stokes’boundary layer model. Coastal Engineering . 40 221–242,2000.
2.Dalrymple, R.A. and Liu, P. L.-F., Water waves over soft muds: a two-layer fluid model. J Phys. Ocean.,8, 1121-1131 , 1978.
3.de Witt, P.J., Liquefaction of cohesive sediments caused by waves, Delft Studies in Integrated Water Management 6, Delft University Press, 1995.
4.Steve Elgar and Britt Raubenheimer, Wave dissipation by muddy seafloors,GEOPHYSICAL RESEARCH LETTERS, VOL. 35, 2008.
5.Forristall, G.Z. and Reece, A.M., Measurements of wave attenuation due to a soft bottom: The SWAMP experiment, Journal of Geophysical Research, Volume 90, Issue C4, p. 3367-3380. ,1985.
6.Forristall, G.Z., Doyle, E.H., Silva, W., Yoshi, M. Verification of a soil wave interaction model (SWIM). In: Davis, A.M. (Ed.), Modeling of Marine Systems, vol. II, pp. 41–68 , 1990.
7.Hsiao, S.V. and Shemdin, O.H., Interaction of ocean waves with a soft bottom. Journal of Physical Oceanography , 10: 605-610,1980.
8.IPPEN, A.T. (ed.) Estuary and Coastline Hydro-dynamics. New York: McGraw-Hill Company , 1966.
9.Lamb, H. Hydrodynamics. Dover, Section 176,art 349,1932.
10.Maa, P.Y. and A.J. Mehta. Soft mud response to water waves. J. waterways, Port, Coastal and Ocean Eng., 116, 634-650,1990
11.McPherson, H. "The attenuation of water waves over a non-rigid bed." J.Fluid Mech., 97(4), 721-742 ,1980.
12.Sakakiyama, T. and Bijker, E. W., Mass transport velocity in mud layer due to progressive waves. J. Waterway, Port, Coastal and Ocean Eng., 115, 5,614-633 , 1989.
13.Shibayama, T., Takikawa, H., and Horikawa, K. "Mud mass transport due to waves." Coastal Engrg. in Japan, Tokyo, Japan, 29, 151-161, 1986.
14.Sterling, G.H., Strohbeck, G.E. Failure of South Pass 70 platform B in Hurricane Camille. J. Pet. Technol. 27, 263–268, 1975.
15.歐彥廷,2008, 規則波通過矩形溝渠內分層密度流體之波動機制研究, 國立成功大學水利及海洋工程研究所碩士論文。