تاثير زاويه و موقعيت آبگير در ميزان دبي رسوب ورودي انحرافي در قوس رودخانه به كمك مدل CCHE2D

Influence of intake’s angel and location on sediment rate in bend of river using CCHE2D software

آبگيرها از جمله سازه‌هايي هستند كه براي برداشت آب از رودخانه ها طراحي و اجراء مي شوند رودخانه ها همراه آب مقداري رسوب با خود حمل مي كنند كه اين رسوب حاصل فرسايش بستر رودخانه و فرسايشي است كه در اثر وقوع بارندگي و يا جاري شدن روانآب سطحي بر روي حوزه آبريز بوجود مي آيد. چنانچه عمل آبگيري از رودخانه صورت گيرد، ورود رسوبات به آبگير، مشكلاتي را به جهت رسوب گذاري به همراه خواهد داشت. در اين تحقيق از مدل رياضي CCHE2D به دليل هزينه كمتر نسبت به روش هاي موجود، تسريع در روند مطالعات و همچنين استفاده از نتايج براي ساير موارد مشابه استفاده شد. به منظور بررسي شرايط هيدروليكي جريان و رسوب در آبگير با زاويه هاي مختلف 30 ،45 ، 60 ، 75 و 90 درجه و موقعيت 25، 40، 55 و70 با مدل رياضي CCHE2D به شبيه سازي دبي و رسوب ورودي به اين آبگير ها پرداخته شده است. نتايج حاصل از آزمايشات نشان مي دهد كه آبگير در موقعيت 70 و زاويه 90 درجه با 4/8 درصد، كمترين رسوب انحرافي به آبگير را دارد. اين گزينه مي تواند مشكل رسوب گذاري و كمبود آب در بعضي از فصول سال را مرتفع سازد.

Investigating the features and flow behavior and related component is one of the complex phenomena that make using of software inevitable. The rivers carry sediment content along with water which is created by erosion of riverbed sediment and erosion caused by rainfall or surface runoff flowing over the catchment area. If the action of river dewatering occurs, the entry of sediment into the intake would make new challenges due to the sedimentation. In particular, these factors are valuable for Meander Rivers which have unsteady flow patterns. There are three general approaches to study this process. numerical model was used in this study due to the lower costs compared to existing methods and expediting the process of result obtaining, the model can also be applied to other similar cases to obtain feedbacks resulting from changes in different components that affect the phenomenon under study conditions and evaluate different functions. In this study, simulation of the discharge and sedimentation input into these intakes was investigated to evaluate the hydraulic conditions of flow and sedimentation in the intake with different angles of 30, 45, 60, 75 and 90 by different location (25, 40, 55 and 70) using CCHE2D numerical model that has a sinusoidal-like turn is analyzed. Besides, variation of parameters like velocity, Froude number, shear stress, river bed elevation and total sediment deposits of the river are calculated and discussed. The impact of these different angles on Hydraulic flow was studied. The results of these tests indicated that intake with 90-degree angle and 70 of arc can improve the flow patterns at the inlet. This can overcome sedimentation problems and water shortages in some seasons.