外文翻譯--孤立波與剛性自然生長(zhǎng)植被的相互作用（原文）

1、Interaction of solitary waves with emergent, rigid vegetationZhenhua Huang a,b,?, Yu Yao a, Shawn Y. Sim a,b, Yao Yao aa School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue,

2、 Singapore 639651, Singapore b Earth Observatory of Singapore (EOS), Nanyang Technological University, 50 Nanyang Avenue, Singapore 639651, Singaporea r t i c l e i n f oArticle history:Received 31 August 2010Accepted 19

3、 March 2011Editor-in-Chief: A.I. Incecik Available online 8 April 2011Keywords:Rigid vegetationMangrove forestDrag coefficientSolitary wavea b s t r a c tIn this study, solitary wave interaction with emergent, rigid vege

4、tation was studied numerically andexperimentally. Laboratory experiments were carried out in a wave flume with vegetation models ofdifferent lengths and porosities; the Boussinesq equations with the effects of the vegeta

5、tion beingmodeled by a quadratic drag law are used to simulate the wave scattering by and the wave propagationthrough vegetation. Effects of incident wave height, vegetation density, and vegetation length arediscussed. A

6、n empirical expression for the mean drag coefficient of emergent, rigid vegetation ispresented and compared with other available data. The results are useful for studying tsunami hazardmitigation by coastal forests.for e

7、xample, Danielsen et al. (2005) and Iverson and Prasad (2007) acknowledged the protective role of coastal vegetation/ mangrove forests. However, there are also some reports claiming that there is no direct link between t

8、he tree belts and tsunami damage mitigation; for example, Baird and Keer (2008) questioned the role of coastal vegetation in mitigating tsunami hazards. With the financial support from several international donors, a USD

9、 62 million program has been endorsed to restore and preserve the coastal vegetation in 12 Asian and African countries for coastal protection against future tsunamis (Baird, 2006). However, our current understanding of t

10、he roles played by mangrove forests in protecting coastal inhabitants against tsunamis is far from complete, hence there is an urgent need to fully evaluate the effectiveness of coastal vegetation in mitigating tsunami h

11、azards. As some information useful for evaluat- ing the effectiveness of mangrove forests in mitigating tsunamis hazard might not be obtainable in post-tsunamis surveys, numericalsimulations are sometimes needed to help

12、understand the tsunami wave interactions with coastal vegetation. Geometrical parameters that are commonly used to character- ize a coastal forest include: forest width (W), number of trees per unit bottom surface area (

13、Nt), averaged tree truck diameter (dt). The forest width is the horizontal extent of the forest in the prevailing flow direction in the forest, and N100 is a measure of the forest density. Another way to describe the for

14、est density is the so-called solid volume portion of a forest (Tanino and Nepf, 2008), which is defined byf ¼ Vs V ð1Þwith Vs being the volume occupied by solid objects in a control volume V. The following

15、 ratio of the solid volume portion to the water volume portion, Vw, has also been used to describe the forest density (Harada and Imamura, 2001)c ¼ Vs Vw ¼ Vs V?Vs ¼ f1?f ð2ÞWhen tsunami waves tr

16、avel through a coastal forest, their energy is dissipated mainly by the turbulence generated by the work done by the drag forces acting on the coastal trees. Thus, modeling of the drag forces on coastal trees is crucial

17、in the numerical studies of tsunami wave propogation in coastal vegetation. When the flow is vertically uniform, the drag force on an isolated circular cylinder (an idealized tree trunk/root) of unit length can be calcul

18、ated byfDðtÞ ¼ Cmrpd2 t 4duðtÞdt þ r2 CddtuðtÞjuðtÞj ð3ÞContents lists available at ScienceDirectjournal homepage: www.elsevier.com/locate/oceanengOcean Enginee

19、ring0029-8018/$ - see front matter Harada and Kawata, 2004; Tanino and Nepf, 2008). Nepf (1999) studied both the mean drag coefficient, turbulence intensity, and diffusion coefficient within emergent, rigid vegetation.

20、The drag-coefficient approach is adopted in this study for its simplicity. For solitary waves, the inertial force is less important com- pared with the drag force, thus the inertial coefficient CM can beArrangement A Arr

21、angement B22 22 Arrangment CFig. 1. Vegetation models used in the experiments. Left: three types of cylinder arrangements used in the experiments (‘ ¼ 0:03 m); Right: a view of the vegetation modelinstalled in the w

22、ave tank.G1 G2 G3 G4 G50.2m 3.0m 0.3mG1 G2 G3 G4 G50.2m 3.0m 0.545m 0.3mG60.545mG1 G2 G3 G4 G50.2m 3.0m 0.545m 0.3mG60.545mG70.545m0.545mFig. 2. The locations of wave probes for different model widths. Top: modelwidth

23、88;0.545 m; middle: model width¼1.090 m; bottom: model width¼1.635 m.Table 1Vegetation models used in the experiments.Model no. Arrangementa f Vegetation width (m)A1 A 0.175 0.545A2 A 0.175 1.090B1 B 0.087 0.54