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بررسی عددی رفتار رسوب گذاری جریان گل آلود رهاسازی توده در محیط دارای لایه بندی | ||
| نشریه مهندسی مکانیک امیرکبیر | ||
| مقاله 5، دوره 51، شماره 6، بهمن و اسفند 1398، صفحه 1235-1252 اصل مقاله (1.05 M) | ||
| نوع مقاله: مقاله پژوهشی | ||
| شناسه دیجیتال (DOI): 10.22060/mej.2018.14062.5789 | ||
| نویسندگان | ||
| صبا تیموری1؛ احسان خواصی* 2؛ حمید یوسفی3 | ||
| 1مهندسی مکانیک، دانشگاه زنجان، زنجان، ایران | ||
| 2گروه مهندسی مکانیک، دانشکده فنی و مهندسی، دانشگاه زنجان | ||
| 3دانشجوی کارشناسی ، مهندسی مکانیک، دانشگاه زنجان، زنجان، ایران | ||
| چکیده | ||
| در این مقاله شبیه‌سازی عددی سه بعدی به منظور مطالعه رفتار رسوب‌گذاری جریان گل آلود رهاسازی توده در محیط دارای لایه بندی چگالی انجام شده است. شبیه‌سازیها به روش شبیه‌سازی گردابه‌های بزرگ انجام شده است. نتایج به دست آمده در حضور لایه بندی تطابق خوبی با نتایج آزمایشگاهی دارند. همچنین حضور لایه بندی چگالی در محیط، باعث کاهش قابل توجه سرعت پیشروی جریان می‌شود، به طوری که مکان پیشانی جریان 57 درصد عقب می‌افتد، ولی تأثیر به-سزایی برروی الگـوی رسـوب‌گذاری ندارد. علاوه بر این، نتایج به دست آمده نشان داد که افزایش شیب تا 12 درجه، باعث افزایش رسوب‌گذاری 15 و 40 درصدی نسبت به شیب‌های 9 و 6 درجه شده است. همچنین، مشاهده شد که افزایش قطر ذرات، باعث کاهش مومنتوم جریان و 75/0 و 7/3 برابر شدن رسوب‌گذاری جریان شده است. با هدف نمایش دقیقتر برهم‌کنش ذرات روی هم، سرعت سقوط ذرات به صورت متغیر با غلظت نیز در نظر گرفته شده است. نتایج این تحلیل نشان می‌دهد که متغیر درنظر گرفتن سرعت سقوط ذرات در مراحل اولیه پیشروی جریان باعث تغییر ناچیزی در سرعت پیشانی می‌شود ولی در ادامه، در نظر گرفتن سرعت سقوط متغیر برای ذرات، سرعت بیشتری را برای پیشانی جریان پیش‌بینی می‌کند. در حالت سرعت متغیر مکان جدایش جریان 22 درصد افزایش می‌یابد. | ||
| کلیدواژه‌ها | ||
| جریان چگال؛ رهاسازی توده؛ محیط لایه‌بندی شده؛ شبیه‌سازی گردابه‌های بزرگ: سطح شیبدار | ||
| عنوان مقاله [English] | ||
| Numerical Study of Lock Exchange Turbidity Current Depositional Behavior in Stratified Environment | ||
| نویسندگان [English] | ||
| Saba Teymouri1؛ Ehsan Khavasi2؛ Hamid Yousefi3 | ||
| 1Department of Mechanical Engineering, University Of Zanjan, Zanjan, Iran. | ||
| 2Mechanical engineering department, University of Zanjan | ||
| 3Department of Mechanical Engineering, University Of Zanjan, Zanjan, Iran. | ||
| چکیده [English] | ||
| In this paper, three-dimensional numerical simulation was conducted to study the lock exchange turbidity current depositional behavior in a stratified environment. Simulations are carried out using Large Eddy Simulation method. The obtained results in stratified case are in good agreement with experimental data. Also, the presence of stratified environment reduces the current velocity, so that the front location is reduced by 57%, but does not have any significant effect on the sedimentation pattern. In addition, the results showed that increasing the slope to 12 degrees increases the sedimentation rate by 15 and 40 percent compared to the slopes 9 and 6 degrees. It was also observed that increasing the particle diameter reduced the momentum and the current sedimentation increases 0.75 and 3.7 times higher. For more accurate representation of the particle interaction, the particle settling velocity also varies with concentration. The results of this analysis indicate that assuming the variable settling velocity in the early stages of the current progression leads to insignificant change in the front velocity, but when the current propagates more, the faster front velocity will be predicted. In variable velocity case, the current separation location increases by 22%.. | ||
| کلیدواژه‌ها [English] | ||
| Density current, Lock-exchange, Stratified environment, Large Eddy Simulation: Sloping bed | ||
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| مراجع | ||
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