The Impact of Long Tree Canopy on Changes in the Force of Solitary Breaking and Non-breaking Coastal waves

Document Type : Research Paper


1 , Faculty of Water Science Engineering, Shahid Chamran University of Ahvaz, Iran

2 Professor, Hydraulic Structures Department, Shahid Chamran University of Ahvaz, Iran.

3 Faculty of Water Science Engineering, Shahid Chamran University of Ahvaz, Iran


Coastal canopy as a Green Belt, can play an important role in reducing the risks on the beach or reconstruction of the coast by reducing waves, accumulation of sediments and soil regeneration. Therefore, the role of coastal canopy in changing the characteristics of beaches and reducing the severity of damage to it through attenuation of high waves is important. The purpose of this study was to investigate the effect of density, width of long tree canopies and wave propagation velocity and to determine the degree of importance of the mentioned cases on the amount of destructive force changes of breaking and Non-breakable waves. To model the tree trunks, rigid wooden stems with a diameter of 1 cm and a height of 30 cm were used. These cylindrical stems were installed on the shore of the flume and the force applied to the obstacles caused by the waves was recorded using the direct measurement method and with the help of an electronic dynamometer (load cell) installed under the moving part of the flume. The experiments were performed with parallel fixed arrangement and variable distances of 5×5 and 10 × 10 and in different widths of 10, 20 and 40 cm and a constant slope of zero. The results show, in a constant canopy width, the maximum increase in force absorption at a density of 5×5 was 1.81 times higher than a density of 10×10. Finally, based on laboratory data, an experimental relationship between drag coefficient and Reynolds number was proposed.


Main Subjects

  • Receive Date: 09 February 2020
  • Revise Date: 02 January 2021
  • Accept Date: 03 January 2021
  • Publish Date: 03 January 2021