نوع مقاله : مقاله پژوهشی
نویسندگان
1 گروه علوم و مهندسی آب، دانشکده کشاورزی، دانشگاه بوعلی سینا، همدان، ایران
2 گروه مهندسی آبیاری و آبادانی، دانشکده کشاورزی و منابع طبیعی کرج، دانشگاه تهران، کرج، ایران
چکیده
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Vegetation has an essential role in altering the flow characteristics of natural channels such as rivers. Efficient hydraulic modeling of flow in compound channels with vegetated floodplains is necessary to understand and determine natural flow processes. In natural or artificial channels, there are different vegetation types with varying densities and heights. The main goal of this study is to investigate the effect of double-layered vegetation on flow characteristics in compound channels using the FLOW-3D model. The results of the numerical model have been calibrated and validated with the results of the physical model of the research of Takuya et al., 2014. Experiments were conducted in 2014 in the hydraulic laboratory of the Akashi National University of Technology in Japan, and in a straight trapezoidal channel with a length and width of 4.8 and 0.8 m respectively. The estimation error of the model for the depth average velocity was in the range of 4 to 6% in the calibration, which was reduced to about 1.5% in the model validation. The average error of water depth estimation was around 3%. There is a good agreement between the numerical model and the physical model for simulation of the flow pattern. The numerical model showed that the vertical profile of the velocity in the floodplain is S-shaped for larger floods when the vegetation is submerged. Vertical velocity profiles are relatively uniform or logarithmic during smaller floods or when short and tall vegetation is emergent. The resistance caused by the presence of vegetation in the floodplains causes a decrease in the flow velocity in the floodplain area of the river and an increase in the capacity of flow transfer in the main channel.
کلیدواژه‌ها [English]
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