کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5474544 | 1520659 | 2017 | 13 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Initiation of motion and scour burial of objects underwater
ترجمه فارسی عنوان
آغاز حرکت و دفن اشیاء زیر آب
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
سایر رشته های مهندسی
مهندسی دریا (اقیانوس)
چکیده انگلیسی
Laboratory experiments were conducted to examine mobility and burial of objects, including onset of motion on a rigid bottom, scour burial into a sand bed, and the interplay between scour and motion onset. Experiments covered a range of object diameter-to-bottom roughness ratios (D/k) of relevance to mobility of unexploded ordnance (UXO). Results indicate that the critical mobility parameter (ÎUcrit) varies as ÎUcrit â 1.6(D/k)â0.72 for cylinders under currents and waves. Modifications of this relation are also presented for accelerating flows. Scour experiments produced formulae for the equilibrium burial depth (Beq) for UXO as a function of the sediment Shields parameter (Îsed) of the form Beq/D = a2 Îsedb2. For current-induced live-bed scour, relatively large cylinders (D >8Â cm) result in a2 â1.3 and b2 â0.36. Smaller cylinders (D <3Â cm) and a tapered shape bury more easily (a2 â15 and b2 â1.1). An alternate, physics based relation for Beq incorporating additional length scales is also presented. For objects on mobile sand under accelerating flow, behavior was observed to be a contest between scour burial and the current speed reaching critical mobility. It is shown that by considering pit depth at the moment of mobility to be the effective bottom roughness, a general explanation of the onset of motion can be obtained.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Ocean Engineering - Volume 131, 1 February 2017, Pages 282-294
Journal: Ocean Engineering - Volume 131, 1 February 2017, Pages 282-294
نویسندگان
Sarah E. Rennie, Alan Brandt, Carl T. Friedrichs,