بررسی اثر موانع نفوذپذیر بر شار هد جریان غلیظ نمکی

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشجوی دکتری، گروه مهندسی عمران، واحد نجف آباد، دانشگاه آزاد اسلامی نجف‌آباد، نجف‌آباد، ایران.

2 استاد، گروه سازه های آبی، دانشکده مهندسی آب و محیط زیست، دانشگاه شهید چمران اهواز، اهواز، ایران

3 استاد، گروه مهندسی آب، دانشکده کشاورزی، دانشگاه صنعتی اصفهان، اصفهان، ایران

چکیده

با توجه به هزینه بسیار زیاد ساخت سد، افزایش طول عمر این سازه عمرانی همواره مورد نظر مهندسین آب بوده است. رسوبات ته‌نشین شده در اطراف دیواره سد سبب کاهش عمر مفید این سازه می‌شود. ساخت مانع در مسیر جریان-های غلیظ و در میانه مخزن می تواند از نزدیک شدن جریانهای غلیظ رسوبی به بدنه سد جلوگیری نموده و جریان را وادار به رسوبگذاری در میانه مخزن نماید و به این ترتیب می‌توان نواحی نزدیک دیواره سد را از مشکل رسوب‌گذاری تا حدی مصون نمود. در این تحقیق اثر موانع نفوذپذیر بر شار هد جریان‌ غلیظ به صورت آزمایشگاهی مورد بررسی قرار گرفته است. طراحی مانع به صورت متخلخل به شکل ذوزنقه‌ای بوده و با ذرات شن با قطر یک سانتی‌متر پر شد و از نمک برای تهیه سیال غلیظ استفاده ‌شد. در این آزمایش‌ها تأثیر دبی ورودی، شیب فلوم و ارتفاع موانع بر رفتار جریان غلیظ مورد بررسی قرار گرفت. با بررسی متغیرهای این تحقیق مشخص شد که درصد کاهش شار هد جریان غلیظ برای نسبت بی‌بعد ارتفاع 1 بین 33 تا 61 درصد، برای نسبت بی‌بعد ارتفاع 1.5 بین 43 تا 63 درصد و برای نسبت بی‌بعد ارتفاع 2 بین 68 تا 100 درصد می‌باشد، همچنین افزایش دبی و شیب ورودی باعث افزایش مومنتم راس جریان شده و در نتیجه سبب کاهش کارایی موانع می‌گردد. علاوه بر این در انتها به مدل‌سازی راس جریان غلیظ به صورت برازش خطی و غیرخطی پرداخته شد.

کلیدواژه‌ها

عنوان مقاله [English]

Investigation of the Effect of Permeable Obstacle on the Head Flux of Salt Density Current

نویسندگان [English]

  • Mehdi Derakhshannia 1
  • Mehdi Ghomeshi 2
  • Seyed Saeid Eslamian 3
  • Seyed Mahmood Kashefipour 2
1 Ph.D. Student, Department of Civil Engineering, Najafabad Branch, Islamic Azad University, Najafabad, Iran.
2 Professor, Hydraulic Structures Department,, Faculty of Water and Environmental Engineering, Shahid Chamran University of Ahvaz, Ahvaz, Iran
3 Professor, Department of Water Engineering, Isfahan University of Technology ,Isfahan, Iran
چکیده [English]

Due to the high cost of construction of the dams, increasing the lifespan of this construction structure has been considered by water engineers. Sediments near the dam wall reduce the useful life of this structure. Constructing obstacles in the path of density currents be is one of the most widely used methods in controlling these sediments. In this study, the effect of permeable obstacles on density current head flux has been studied experimentally. The obstacles were made in the shape of trapezoid and were filled with sand particles with a diameter of one centimeter also salt were used to prepare the density current. In these experiments, the effect of inlet flow, flume slope and obstacle height on density current was investigated. Examining the variables of this study, it has been found that the reduction percentage of the density current head flux for the dimensionless ratio of height 1 is between 33.1 to 61%, for the dimensionless ratio of height 1.5 is between 43.2 to 63.3% and for the dimensionless ratio of height 2 is between 68.2 to It is 100%, also increasing the inlet flow ratio and flume slope increases the momentum of the current and thus reduces the efficiency of the obstacles. In addition, at the end, the density current head was modeled as linear and nonlinear regression.

کلیدواژه‌ها [English]

  • Density currents
  • Permeable obstacles
  • Sedimentation
  • Sediment transfer

مراجع

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مدیریت آب و آبیاری
دوره 11، شماره 1
اردیبهشت 1400
صفحه 1-14

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