A study on the drag coefficient in wave attenuation by vegetation

Abstract. Vegetation in wetlands is a large-scale nature-based resource providing myriad of services for human beings and the environment, such as dissipating incoming wave energy protecting coastal areas. For understanding height attenuation by vegetation, there are two main traditional calibration approaches to drag effect acting on vegetation. One them based rule that decays through vegetated area reciprocal function another an exponential function. In both functions, local reduces with distance from beginning vegetation depending damping factors. These factors, which usually obtained measured height, linked coefficient measurable parameters, respectively. So quantifies can be calculated different methods, followed connecting this hydraulic parameters make it predictable. study, relations between these factors methods calculate have been investigated 99 laboratory experiments. Finally, relevant were analyzed. The results show emergent conditions should considered when studying coefficient; had overlooked condition cannot perform well was emerged. new method relation performed well-recognized emerged submerged Additionally, Keulegan–Carpenter number suitable parameter predict only experimental setup, especially densities affect prediction equations.