انجمن هیدرولیک ایران نشریه علمی هیدرولیک 2345-4237 6 3 2011 11 22 Development of Unsteady State Bed Variations Simulation Model in Gravel Bed Rivers توسعه مدل شبیه سازی تغییرات بستر رودخانه های شنی تحت جریان ناپایدار با رسوب ورودی از بالادست 55 72 85488 10.30482/jhyd.2011.85488 FA مهدی باقری نژاد محمدرضا مجدزاده طباطبایی عضو هیات علمی/ پردیس فنی مهندسی شهید عباسپور- دانشگاه شهید بهشتی 0000-0002-6205-7868 سید سعید موسوی ندوشنی Journal Article 2011 03 23 Obtaining an analytical solution for bed variation equations, is a hard task and often impossible.<br />However, if a quasi–steady state is considered for flow condition, analytical solution may not be<br />unreachable provided that necessary simplifications are made. The main purpose of this paper is to<br />develop an analytical model to predict bed variations in flood conditions with upstream sediment<br />supply. In this study, non–uniformity of bed material size has been considered by hiding function. In<br />addition, governing equations have also been applied and solved to compute values for unknown<br />parameters such as hydraulic parameters, bed material size, water surface slope and elevation and bed<br />load at various times from the beginning of flooding. Model validation with observed experimental<br />data have been made and followed by sensitivity analysis. Finally the effect of flood hydrograph<br />shapes has also been investigated on bed variations in gravel bed rivers. Results have shown that<br />hiding function has modeled non–uniformity of the bed materials appropriately while a reasonable<br />agreement has been found with observed experimental data for flow Froude number of less than 0.8. https://jhyd.iha.ir/article_85488_56774c607fa6ae69d2864307508dbce2.pdf