کد مقاله کد نشریه سال انتشار مقاله انگلیسی ترجمه فارسی نسخه تمام متن
651119 1457405 2016 8 صفحه PDF سفارش دهید دانلود رایگان
عنوان انگلیسی مقاله ISI
The formation and migration of sand ripples in closed conduits: Experiments with turbulent water flows
ترجمه فارسی عنوان
شکل گیری و مهاجرت امواج شن و ماسه در لوله های بسته: آزمایش با جریان آشفته جریان
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موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی جریان سیال و فرایندهای انتقال
چکیده انگلیسی


• We investigate the formation and migration of sand ripples in closed conduits.
• Turbulent water flows were imposed over a granular bed in a transparent channel.
• The growth and migration of ripples were filmed by a high-definition camera.
• The length and celerity of ripples were determined by post-processing the images.

The transport of solid particles by a fluid flow is frequently found in nature and industry. Some examples are the transport of sand in rivers and hydrocarbon pipelines. When the shear stresses exerted by a fluid flow on a granular bed remain moderate, some grains are set in motion without fluidizing the bed; the moving grains form a layer, known as bed load, that moves while maintaining contact with the fixed part of the bed. Under bed load conditions, the granular bed may become unstable, generating ripples and dunes. Sand ripples are commonly observed in closed conduits and pipes such as in petroleum pipelines, sewer systems, and dredging lines. Although of importance for many scientific domains and industrial applications, the formation of ripples in closed conduits is not well understood, and the problem is still open. This paper presents an experimental study on the formation and migration of sand ripples under a turbulent closed-conduit flow and bed-load conditions. In our experiments, fully-developed turbulent water flows were imposed over a granular bed of known granulometry in a transparent channel, and bed load took place. For different water flow rates and grain diameters, the growth and migration of bedforms were filmed by a high-definition camera, and a numerical code was developed to determine the wavelength and celerity of the bedforms from the acquired images. The obtained results are compared with published stability analyses.

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ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Experimental Thermal and Fluid Science - Volume 71, February 2016, Pages 95–102
نویسندگان
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