arXiv 0909.22762009-09-12physics.flu-dynphysics.comp-ph

Nonlinearity in Oscillatory Flow over Sand Ripple

Ruma Dutta, Ethan Kubatko

备注：: This is 5 pages with 4 figures. submitted to Mechanica

英文摘要：

In this report, We investigated the nonlinear phenomena in the study of flow dynamics of velocity component. In our studies, we observed nonlinear term in the vertical component of velocity by vittori et al \cite{vit} The time series simulation of vertical component which increases with Reynold stress value. We developed direct numerical simulation under two dimensional grid system to study the flow dynamics and vorticity parameter. Flow pattern and flow dynamics near wavy boundary wall in the victinity of ripple bottom was readdressed under direct numerical simualtion(DNS) framework.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

阅读原文

阅读 PDF ↗

arXiv 页面 ↗HTML 原文 ↗

本文内容

英文摘要相关论文

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

继续探索

相关论文

Three-dimensional sand ripples as the product of vortex instability

Three-dimensional sand ripples can be observed under steady liquid flows in both nature and industry. Some examples are the ripples observed on the bed of rivers and in petroleum pipelines conveying sand. Although of importance, the formation of these patterns is not completely understood. There are theoretical and experimental evidence that aquatic ripples grow from two-dimensional bed instabilities, so that a straight vortex is formed just downstream of their crests. The proposition of Raudkivi (2006), that three-dimensionality has its origin in a vortex instability, is employed here. This p…

2016-08-13physics.flu-dyn

Formation of sand ripples under a turbulent liquid flow

Sand ripples are commonly observed in both nature and industry. For example, they are found on riverbeds and in oil pipelines that transport sand. In both natural and industrial cases, ripples increase friction between the bed and fluid and are related to flooding, high pressure drops, and transients. Ripples appear when sediments are entrained as bed load (a mobile granular layer) and are usually considered to be the result of initial bedforms that eventually saturate. Given the small aspect ratio of the initial bedforms, linear analyses can be used to understand the formation of ripples. Thi…

2016-08-20physics.flu-dyn

The formation and migration of sand ripples in closed conduits: experiments with turbulent water flows

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…

2016-08-16physics.flu-dyn

Direct numerical simulations of ripples in an oscillatory flow

Sea ripples are small-scale bedforms which originate from the interaction of an oscillatory flow with an erodible sand bed. The phenomenon of sea ripple formation is investigated by means of direct numerical simulation in which the sediment bed is represented by a large number of fully-resolved spherical grains. Two sets of parameter values are adopted which are motivated by laboratory experiments on the formation of laminar rolling-grain ripples. The knowledge on the origin of ripples is presently enriched by insights and by providing fluid- and sediment-related quantities that are difficult …

2018-10-23physics.flu-dyn

地球至火星大气压下活跃跃移期间波纹床面的空气动力学粗糙度

Aerodynamic roughness of rippled beds under active saltation at Earth-to-Mars atmospheric pressures

本研究在地球至火星气压范围内测量活跃跃移下平衡波纹沙床的空气动力学粗糙度 z_0，发现外推至火星时形状阻力可能占主导，z_0 最高达 1 厘米。

2025-06-16physics.flu-dynphysics.geo-ph

Concentration profiles for fine and coarse sediments suspended by waves over ripples: An analytical study with the 1-DV gradient diffusion model

Field and laboratory measurements of suspended sediments over wave ripples show, for time-averaged concentration profiles in semi-log plots, a contrast between upward convex profiles for fine sand and upward concave profiles for coarse sand. Careful examination of experimental data for coarse sand shows a near-bed upward convex profile beneath the main upward concave profile. Available models fail to predict these two profiles for coarse sediments. The 1-DV gradient diffusion model predicts the main upward concave profile for coarse sediments thanks to a suitable $β$(y)-function (where $β$ is …

2010-11-28physics.flu-dyn

更多相关论文收起更多论文

地球上共同演化的气动沙纹与撞击沙纹

Coevolving aerodynamic and impact ripples on Earth

本研究通过风洞实验与数值模拟发现地球上存在共同演化的厘米级撞击沙纹与分米级气动沙纹，揭示两种中尺度不稳定性，修正了风沙响应速度的认知，并提出太阳系中尺度颗粒床形地貌的统一框架。

2025-01-18cond-mat.softphysics.flu-dynphysics.geo-ph

Linear and nonlinear instabilities of a granular bed: determination of the scales of ripples and dunes in rivers

Granular media are frequently found in nature and in industry and their transport by a fluid flow is of great importance to human activities. One case of particular interest is the transport of sand in open-channel and river flows. In many instances, the shear stresses exerted by the fluid flow are bounded to certain limits and some grains are entrained as bed-load: a mobile layer which stays in contact with the fixed part of the granular bed. Under these conditions, an initially flat granular bed may be unstable, generating ripples and dunes such as those observed on the bed of rivers. In fre…

2016-08-22physics.flu-dyn

Toward Improving Prediction of Sediment Transport over Wave-Induced Ripples

Sediment transport over wave-induced ripples is a very complex phenomenon where available models fail to provide accurate predictions. For coastal engineering applications, the 1-DV advection-diffusion equation could be used with an additional parameter α related to the process of vortex shedding above ripples (Absi, 2010). The aim of this study is to provide simple practical analytical tools. An analytical eddy viscosity profile was validated by DNS data of turbulent channel flows (Absi et al., 2011). In this study, we will show that: (1) the period-averaged eddy viscosity in oscillatory boun…

2011-06-06physics.flu-dynphysics.geo-ph

Euler-Lagrange模拟中沉积物床面上振荡边界层的动力学

Dynamics of an oscillatory boundary layer over a sediment bed in Euler-Lagrange simulations

本文通过多雷诺数Euler-Lagrange模拟，揭示振荡边界层与可运动沉积床通过渗透性和颗粒反馈强耦合，并解释沙纹、悬浮及Shields数降低机制。

2025-10-03physics.flu-dyn

Sediment transport under oscillatory flows

The results of Direct Numerical Simulations of the oscillatory flow over a cohesionless bed of spherical particles, mimicking sediment grains, are described. The flow around the sediment particles is explicitly computed by using the immersed boundary method, which allows the force and torque acting on the particles to be evaluated along with their dynamics. Different values of the Reynolds number and different values of the ratio between the grain size and the thickness of the boundary layer are considered such that the results are useful to quantify the sand transport generated by sea waves i…

2020-09-03physics.app-phphysics.flu-dynphysics.geo-ph

Stokes边界层对振荡流中颗粒对动力学的影响

The effect of the Stokes boundary layer on the dynamics of particle pairs in an oscillatory flow

本文通过直接数值模拟和浸入边界方法比较振荡盒与振荡槽道流中的颗粒对动力学，揭示底部Stokes边界层引入额外无量纲参数并导致两者仅在有限参数范围内等价。

2022-07-26physics.flu-dyn

Sediment Micromechanics in Sheet Flows Induced by Asymmetric Waves: A CFD-DEM Study

Understanding the sediment transport in oscillatory flows is essential to the investigation of the overall sediment budget for coastal regions. This overall budget is crucial for the prediction of the morphological change of coastline in engineering applications. Since the sediment transport in oscillatory flows is dense particle-laden flow, appropriate modeling of the particle interaction is critical. Although traditional two-fluid approaches have been applied to the study of sediment transport in oscillatory flows, the approaches do not resolve the interaction of the particles. Particle-reso…

2016-05-27physics.comp-phphysics.flu-dynphysics.geo-ph

Direct numerical simulation of the oscillatory flow around a sphere resting on a rough bottom

The oscillatory flow around a spherical object lying on a rough bottom is investigated by means of direct numerical simulations of continuity and Navier-Stokes equations. The rough bottom is simulated by a layer/multiple layers of spherical particles, the size of which is much smaller that the size of the object. The period and amplitude of the velocity oscillations of the free stream are chosen to mimic the flow at the bottom of sea waves and the size of the small spherical particles falls in the range of coarse sand/very fine gravel. Even though the computational costs allow only the simulat…

2017-06-12physics.flu-dyn

部分饱和/非饱和介质中一维振荡流的广义Green-Ampt方法：海滩流体动力学中的毛细效应（半解析与数值研究）

Generalized Green-Ampt Approach to 1D Oscillatory Flows in Partially Saturated/Unsaturated Media: Capillary Effects in Beach Hydrodynamics (Semi-analytical & Numerical studies)

本研究提出部分饱和多孔介质潮汐振荡下水位响应的广义Green-Ampt多锋面半解析方法，兼顾毛细与重力效应，计算效率高且精度优于单锋面模型，可用于分析非饱和流系统的振荡响应。

2024-09-16physics.flu-dyn