開水路非定常流の相似律に関する問題点

Abstract

The hydraulic similitude to guarantee any scale model test for one-dimensional flowsin pipes and open channels can be derived from one-dimensional equations of continuity, energy or linear momentum in the control volume method of hydraulic analysis.Recently, the first author has derived the exact formulation of one-dimensional systemof equations of continuity, energy and linear momentum in the curvilinear orthogonalcoordinates from the original system in theoretical hydrodynamics, and the authors haveshown a special system of equations for the open channel flow in a rectangular channel.The results obtained indicate that the classical dynamic equation must be supplementedby additional terms concerning three-dimensional variations of transverse velocity andstage in the unsteady behaviour, which suggests the classical treatment for the hydraulicsimilitude of unsteady open channel flows should be modified. This paper treats withthe order effects of additional terms to the classical equation for the unsteady open channelflow and the derivation of new formulation for the hydraulic similitude of unsteady openchannel flows.Preliminary experimentations made in a laboratory test flume will also verify thetheoretical results and predict careful treatments for proceeding the hydraulic scale testwith distorted dimensions.