A Series of Experiments Investigating Wave Attenuation through Artificial Marsh Grass

摘要

A series of experiments investigating the dissipation of wave energy by artificial Spartina alterniflora were completed using a large-scale flume at the U.S. Army Engineer Research and Development Center. A previous experiment identified trends in wave attenuation with respect to hydrodynamic and plant parameters, changes in spectral shape, and parameterized the bulk drag coefficient. However, the trends with respect to wave height and peak period were indefinite and unexplained behavior of the bulk drag coefficient between submerged and emergent conditions led to a subsequent experiment that spanned a wider range of Reynolds numbers and degrees of plant submergence. Plant submergence is again shown to be a crucial variable affecting the degree of wave attenuation. Wave attenuation slightly increased with wave height at all modeled water depths whereas wave attenuation with respect to peak wave period depended on plant submergence. Accounting for bottom friction in the Mendez and Losada (2004) approach better collapsed the bulk drag coefficient across water levels, although two different curves, one for emergent and one for submerged conditions, were evident.