کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
9479229 1325275 2005 17 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Transient ripples in oscillatory flows
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات زمین شناسی
پیش نمایش صفحه اول مقاله
Transient ripples in oscillatory flows
چکیده انگلیسی
Laboratory measurements are reported of the change in ripple profile with time in response to a step change in flow conditions. The ripples were formed in beds of sand in an oscillating tray rig. Spectra of the bed profiles were obtained with a miniature echo sounder traversed over the bed. Two different growth mechanisms for the new bed profile were observed. In one case the new profile grows from an existing small perturbation of the bed at the same wavenumber as that of the final bed. In the second mechanism the ripple wave length gradually changes with time to fit the new conditions. Rates of growth of the new bed and decay of the old bed are analysed and empirical formulas are derived. These formulas are used to estimate transition times for rippled beds responding to changed flow conditions. Comparison with measured transition times shows significant scatter.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Continental Shelf Research - Volume 25, Issue 4, March 2005, Pages 485-501
نویسندگان
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