AMPLIFICATION CHARACTERISTIC OF AN UNDULAR BORE IN MEANDERING CHANNEL

Abstract

 We focus on an undular bore of tsunami run-up in rivers. To clarify an amplification characteristic of the undular bore in meandering rivers, we conducted the basic experiment and calculated it using the two- or three- calculation. The experimental results of wave height show that the amplification characteristic along the outer bank is different depend on channels. The longitudinal tendency of amplification is expressed by the two-dimensional calculation results. The three-dimensional calculation results corresponded to experimental results of the initial wave height. The experimental and calculation results showed us that the soliton fission amplification of the meandering channel of small sinuosity is larger than that of big sinuosity and the longitudinal increase of the wave height along the outer bank. We confirm the bore impinging on the outer wall of meandering channel and the wave height along the outer bank increased. For that reason, the soliton fission amplification occurs. Both calculation results are coincident with the profile of bore head’s line in meandering channels and can express the mechanism of the soliton fission amplification. The soliton fission amplification along the outer bank occurs in the meandering channel of small non-dimensional width. The bigger the sinuosity is, the larger the soliton fission amplification is.