مهندسی مکانیک مدرس

مهندسی مکانیک مدرس

شبیه‌سازی عددی پخشیدگی رسوب بستر با قابلیت مدل‌سازی سطوح خشک با استفاده از حل‌کننده ریمن تقویت‌شده

نویسندگان
1 دانشگاه بیرجند، بیرجند، ایران
2 دانشگاه بیرجند
3 استادیار و عضو هیئت علمی دانشگاه بجنورد
چکیده
روش‌های عددی مختلفی برای حل سیستم‌های مورفودینامیک توسعه یافته است که در میان این روش‌ها، در سال‌های اخیر روش حجم محدود به‌طور گسترده‌ای مورداستفاده قرار گرفته است. در این پژوهش یک روش حجم محدود کارآمد برای شبیه سازی انتقال رسوب بستر در نزدیکی سطوح خشک، ارائه می شود. معادلات حاکم بر انتقال رسوب در کانال‌ها و رودخانه‌ها شامل معادلات آب کم‌عمق و اکسنر می‌باشند. با در نظر گرفتن یک سرعت نوین برای امواج ریمن، معادلات آب کم‌عمق و اکسنر توسط روش جفت شده ضعیف بر اساس حل‌کننده ریمن تقویت‌شده، حل می‌شوند. در این روش ابتدا معادله اکسنر حل می‌گردد و سپس تغییرات بستر به‌روز شده با همان ساختار ریمن، به عنوان عبارت منبع در معادلات آب کم‌عمق استفاده می‌شود. حل‌کننده ریمن تقویت‌شده بر اساس تجزیه‌ای از بردار تقویت‌شده شامل عمق جریان، اندازه حرکت، شار اندازه حرکت و تراز بستر می‌باشد. مدل عددی ارائه‌شده ابتدا برای شبیه‌سازی شکست سد بر روی بستر متحرک به کار گرفته شد. سپس مسئله شکست سد ناشی از روگذری جریان در نظر گرفته شد و داده‌های محاسبه‌شده با نتایج آزمایشگاهی مقایسه گردید. نتایج عددی حاصل بیانگر آن است که روش جفت شده ضعیف که بر مبنای روش ریمن تقویت‌شده، توسعه یافته است، قابلیت مدل‌سازی انتقال رسوب در نزدیکی سطوح خشک با دقت بالا را دارا می‌باشد و در نمونه‌های آزمایشی تطابق بسیار خوبی با داده آزمایشگاهی دارد.
کلیدواژه‌ها

موضوعات


عنوان مقاله English

Numerical simulation of bedload sediment transport with ability to model dry interfaces using an augmented Riemann solver

نویسندگان English

Mina Barzgaran 1
Hossein Mahdizadeh 2
Salman Pouresmael 3
1 Department of Civil Engineering, faculty of Engineering, University of Birjand, Birjand, Iran
2 Faculty member of Birjand University
3 Department of Civil Eng, University of Bojnord, Iran
چکیده English

Various numerical methods have been developed for solving morphodynamic systems, among which the finite-volume method has been widely employed in recent years. This paper presents an efficient finite volume technique for simulation of bedload sediment transport near dry interfaces. The equations governing sediment transport in channels and rivers comprise the shallow water equations and Exner equation. By considering a novel velocity for Riemann waves, shallow water and Exner equations are solved using a weakly-coupled scheme based on an augmented Riemann solver. In this approach the morphodynamic equation is first solved and the updated bedload changes with the same Riemann structure are used as a source term within the shallow water equations. Augmented Riemann solver is based on a decomposition of an augmented vector—the depth, momentum as well as momentum flux and bottom surface. The proposed numerical model is first used for the simulation dam break flow over a mobile bed. Then, dam failure due to over-topping flow is considered and the computed results are compared with the experimental data.These numerical results indicate that the defined weakly coupled method developed based on an augmented Riemann technique is able to be used for modelling bedload sediment transport near dry interfaces with highly accurate and exhibits a very good agreement with the experimental data for test cases.

کلیدواژه‌ها English

Shallow Water
Godunov
Conservation laws
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