An Experimental Study on a Characteristics of Flow around Groyne Area by Install Conditions

Joongu Kang

doi:10.4236/eng.2012.410081

Abstract

In designing group groynes, the space of the groynes is an important factor, and the flow between the groyne areas will vary along the space. Since the flow in the groyne field significantly affects the flow change, the bed change, the bank erosion and the condition of the habitat, an assessment of the flow along the space of the groynes will yield important data needed to diversify the object of the groyne installation. To provide basic data for the determination of the proper space of groynes in a groyne group, the flow in the channel and groyne field, which varies with the installation of the groyne, is herein analyzed. The space of the groynes was set from the same length to 12 times the length of the groyne, and the flow range was measured using the LSPIV method and ADV. The influence of the angle of the installation was also analyzed. As a result, through the flow configuration in the groyne field and the flow range at the center of the groyne field against the space of the groyne, the decreasing influence of groyne erosion was suggested by the analysis of the shelter effect of aquatics and the countercurrent in the bank line.

Highlights

A groyne is a structure installed in the front part of a bank or a bank line for protection, flow control, ensuring of the depth of the main channel, etc
Since the flow in the groyne field significantly affects the flow change, the bed change, the bank erosion and the condition of the habitat, an assessment of the flow along the space of the groynes will yield important data needed to diversify the object of the groyne installation
Through the flow configuration in the groyne field and the flow range at the center of the groyne field against the space of the groyne, the decreasing influence of groyne erosion was suggested by the analysis of the shelter effect of aquatics and the countercurrent in the bank line

Summary

Introduction

A groyne is a structure installed in the front part of a bank or a bank line for protection, flow control, ensuring of the depth of the main channel, etc. FHWA [7] suggested considering the length, angle, transmissivity, and curvature of the curved channel of the groyne, the general range of which was L/l = 1 - 6, for the purpose of groyne installation and protection. The results of the research of FHWA expressed the length of the bank protected by each groyne into the flow extension angle, which indicates the angle from the vertical hem of the groyne to the line of the groyne that ends the recirculation zone. The previous researches show experimental results based on the installation purpose (groyne protection, flow control, etc.), but failed to suggest the data for the flow characteristics (the increasing flow velocity in the channel and the vortex phenomenon in the groynefield) at the channel and groyne fields along the space of the groynes. This study aims to analyze the influence of the flow along the space of the groynes and to derive data to suggest the space of the groynes through an irrigating model test

Existing Studies

Flow Analysis at the Groyne Field along the Groyne Installation Angle

Findings

Conclusions