نتایج جستجو برای: bedform

تعداد نتایج: 222  

Journal: :Frontiers in Physics 2021

A sand surface subjected to a continuous wind field exhibits regular ripple surface. These aeolian ripples emerge and develop under the coupling effect between field, bed topology, particle transportation. Lots of theoretical numerical models have been established study since last century, but none them has capability directly reproduce 3D long-term development them. In this work, novel model w...

Journal: :Journal of Earth and Marine Technology 2022

The study of facies analysis and interpretation the depositional environment Lemat Formation located at Bukit Tiga Puluh aims to clarify problems found in Paleogene sediments South Sumatra Basin. A detailed fluvial has been carried out Lubuk Bernai track. number observations, profiling, measured stratigraphic section have out. stratigraphy area can be divided into 5 units from old young, namely...

Journal: :AIP Advances 2023

Seepage is one of the important factors involved in natural flow conditions, contributing to changes turbulence patterns and morphological due transport sediments. This sediment particles influences development fluvial bedforms any river channel. However, previous research on dynamics has not considered influence seepage field over bedforms. The present experimental aims explore behavioral turb...

پایان نامه :دانشگاه تربیت معلم - تهران - دانشکده ادبیات و علوم انسانی 1389

آشکارسازی تغییرات ساحلی-رودخانه ای و بررسی ویژگیهای ژیومورفولوژیکی سیستم های رودخانه ای و چگونگی تحول آن یکی از نیازهای اساسی برای برنامه ریزان محیطی و منطقه ای می باشد. رودخانه دز یکی از پرآب ترین رودخانه های کشور که به علت احداث سدهای مهم بر روی ان و همچنین به عنوان یکی از شعبات کارون حایز اهمیت است. آشکار سازی بستر رودخانه دز و عوامل طبیعی و انسانی موثر بر تغییرات مذکور با استفاده از تکنیک ...

2014
Tian-Jian Hsu Fengyan Shi

The interaction between the hydrodynamics and complex bathymetry can produce highly heterogeneous and locally energetic flows, e.g., in a tidal inlet dominated by tidal flow and wave-current interaction. Consequently, the morphological evolution around such tidal inlet also becomes very dynamic. These two factors cause concerns over navigation safety especially in areas where routine surveys ar...

2006

Preliminary results are reported from an experimental study of the interaction between turbulence, sediment transport and bedform dynamics over the transition from dunes to upper stage plane beds. Over the transition, typical dunes changed to humpback dunes (mean velocity 0.8 ms-', depth 0.1 m, mean grain size 0.3 mm) to nominally plane beds with low relief bed waves up to a few mm high. All be...

2007
P. A. Tassi S. Rhebergen O. Bokhove

The accurate representation of morphodynamic processes and the ability to propagate changes in the riverbed over a wide range of space and time scales make the design and implementation of appropriate numerical schemes challenging. In particular, requirements of accuracy and stability for medium and long term simulations are difficult to meet. In this work, the derivation, design, and implement...

2000
Jaco H. Baas James L. Best

Fries et al. (1999), hereafter referred to as FBW, present interesting experimental data showing that biogenic mounds, formed by the conveyor-belt feeding polychaete Cistenides (Pectinaria) gouldii, can be reshaped into asymmetric bedforms at bed shear stresses below the Shields threshold of sediment movement. The ®nal geometry of the current ripples was found to depend on the spatial density o...

2016
TIMOTHY T. CREYTS CHRIS R. STOKES MARTIN MARGOLD

Rapidly-flowing ice streams are an important mechanism through which ice sheets lose mass, and much work has been focussed on elucidating the processes that increase or decrease their velocity. Recent work using standard inverse methods has inferred previously-unrecognised regular patterns of high basal shear stress (‘sticky spots’ >200 kPa) beneath a number of ice streams in Antarctica and Gre...

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