The study of hydraulic parameters affecting on erision, deposition and, meandring of GHEZEL OUZAN river, Volume 3 (Mathematical model)

in this research using finite volume method a two dimensional mathematical model is developed for predicting the changes of river morphology. The developed computer package can he used specially for calculating river bank erosion and sedimentation in meander loops, The BASIC language is used for computer programming. In the prepared model firstly, by solving energy, velocity diffusion and momentum equations, flow parameters including main velocities distribution, secondary velocities, distribution main and secondary shear stresses and critical shear stresses are determined. Then by calculating the critical flow velocity and its comparison with the longitudinal velocity, the rates of sediment transport in longitudinal direction for each sub section are computed. After that the transversally transported sediment rate (or erosion) is determined through comparing the calculated bed shear stresses in the two main directions, and by calculating sediment exchange among the subsections based on mass continuty equations. In this manner, the erodibility parameter is calculated for each river section and by using periodic wave model the river plan changes is predicted. This investigations has indicated that: _ The most suitable grid for dissolving of the equations is 50x20 grid. _ The finite volume method can be suitably used for analysis of natural river morphology problems. _ In dissolving the equations set, comparing with the other methods the point by point method, inspire of its simplicity, has shown a suitable accuracy. _ The best numerical methods for dissolving of equations set (least time, suitable accuracy of answers) are the point by point (PBP) and line by line up to down (LBLUTD) methods, respectively. _ Ghezel ouzan river has a parabolic velocity distribution and the exponent of the suggested equation varies between 3 to 8. _ The maximum displacement of Ghezel ouzan river is different in various places and it depends on discharge and slope. The prepared model is very sensitive 10 the variation of discharge and slope. _ _ _ _ _ _ _ _ MINISTRY OF JAHAD -E- SAZANDEGHI DEPARTMENT OF EDUCA nON AND RESEARCH _ TITEL:The study of hydraulic parameters affecting on erision, deposition and, meandring of GHEZEL OUZAN river, Volume 3 (Mathematical model) EXECUTER : Dr. M. Habibi UNIT OF EXECUTION: Soil Conservation and Watershed Management Research Center - Dept. of River Engineering DATE OF PUBLISHING: FEB. 1998 _ THIS PLAN WITH F ARV AST NUMBER HAS REGISTERED IN PUBLICA TlONS COMMITTEE OF RESEARCH AND EDUCATION DEPARTMENT OF MINISTRY OF JAHAD -E- SAZANDEGHI ON . THE RIGHT OF PUBLISHING IS LIMITED JUST FOR EDITOR, SA YJNG OF ITEMS, AND SHOWING OF PICTURES, TABLES AND GRAPHS WITH MENTIONING OF REFRENCE IS ALLOWED.