کد مقاله کد نشریه سال انتشار مقاله انگلیسی ترجمه فارسی نسخه تمام متن
1721112 1014466 2011 17 صفحه PDF سفارش دهید دانلود رایگان
عنوان انگلیسی مقاله ISI
Laboratory investigation of pressure gradients induced by plunging breakers
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موضوعات مرتبط
مهندسی و علوم پایه سایر رشته های مهندسی مهندسی دریا (اقیانوس)
پیش نمایش صفحه اول مقاله
Laboratory investigation of pressure gradients induced by plunging breakers
چکیده انگلیسی
This investigation presents laboratory observations on the spatio-temporal evolution of pressure fields and gradients induced by plunging waves propagating across the nearshore zone. Experiments were carried out to obtain detailed measurements of pressure time-curves and fluid velocities across the shoaling, breaking and swash zones. Pressure envelopes showed a consistent shape in all tests, with minimum values in the swash zone and maximum values at the impinge points. In particular, the nature of the pressure gradient at different locations (shoaling, breaking and swash zones) across the impermeable bed is investigated, revealing maximum values at the impact points. The relationship of the pressure gradient to horizontal velocity and local acceleration is also examined. This investigation enabled the elucidation of an apparent contradiction identified in recent works regarding the relationship between local acceleration and pressure gradient within the surf and swash zones. Consistent with findings of prior studies, results in the shoaling and breaking zone indicated that local fluid accelerations can be used to account for the contribution of pressure gradients. In contrast, the validity of this assumption is not established within the swash zone. In this region, minimum pressure gradients are identified and local acceleration is negative (offshore) for almost the whole swash cycle, consistent with previous field observations. Thus, for plunging breakers driven-swash, results point toward the significance of the advective terms acting against local acceleration. Furthermore, measurements of the velocity field by a validated Bubble Image Velocimetry (BIV) technique provide a qualitative description of the highly aerated flow, revealing that maximum values of vertical velocities are associated with the wave-impact from a plunging breaker impinging on the bed. These results indicate the need for a detailed characterisation of the pressure gradient under different types of wave breaking.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Coastal Engineering - Volume 58, Issue 8, August 2011, Pages 722-738
نویسندگان
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