نتایج جستجو برای: shallow flow

تعداد نتایج: 515134  

Journal: :محیط زیست طبیعی 0
سید حسین خزاعی عضو هیأت علمی دانشکده منابع طبیعی دریا، دانشگاه علوم و فنون دریایی خرمشهر، ایران نعمت ا... خراسانی استاد دانشکده منابع طبیعی، دانشگاه تهران، ایران خلیل طالبی جهرمی استاد دانشکده کشاورزی، دانشگاه تهران، ایران مجید احتشامی استادیار دانشکده عمران، دانشگاه خواجه نصیرالدین طوسی، ایران

most areas of plain regions in mazandaran province are planted with rice, and different pesticides and fertilizers are used at high densities to increase the yield of production. diazinon is the main insecticide that being used to control chilo supressalis walker. the main problem is the high groundwater table in the region, and consumption of this water by local people and anthropogenic side e...

2004
Huazhong Tang Tao Tang Kun Xu

In this paper, the Kinetic Flux Vector Splitting (KFVS) scheme is extended to solving the shallow water equations with source terms. To develop a well-balanced scheme between the source term and the flow convection, the source term effect is accounted in the flux evaluation across cell interfaces. This leads to a modified gas–kinetic scheme with particular application to the shallow water equat...

2004
Roberto Basili Nicola Lorusso Maria Teresa Pazienza Fabio Massimo Zanzotto

In this paper we describe the agent based architecture and extensively report the design of the shallow processing model in it. We present the general model describing the data flow and the expected activities that have to be carried out. The notion of question session will be introduced as a means to control the communication among the different agents. We then present a shallow model mainly b...

2006
S. D. Howison J. R. Ockendon

This paper describes how tangential impact velocities can be incorporated into wellknown impact theories in deep and shallow water. Taking the deep and shallow flows in turn, it is shown how to link the normal impact Wagner and Korobkin theories to the tangential impact theories of planing and skimming respectively. An instability is revealed that limits the configurations that can be analysed ...

Journal: :Physical review letters 2012
Thierry Foglizzo Frédéric Masset Jérôme Guilet Gilles Durand

Despite the sphericity of the collapsing stellar core, the birth conditions of neutron stars can be highly nonspherical due to a hydrodynamical instability of the shocked accretion flow. Here we report the first laboratory experiment of a shallow water analogue, based on the physics of hydraulic jumps. Both the experiment and its shallow water modeling demonstrate a robust linear instability an...

2010
Pierfranco Costabile Carmelina Costanzo Francesco Macchione

In this paper a comparative analysis of 2D numerical models for overland flow simulations have been performed; in particular they are based on the shallow water approach according to fully dynamic, diffusive and kinematic wave modeling. The systems have been numerically solved by using the MacCormack second order central scheme. The models have been tested, validated and compared using numerica...

Journal: :SIAM Journal of Applied Mathematics 2003
Anthony J. Roberts Z. Mei Zhenquan Li

Consider the dynamics of turbulent flow in rivers, estuaries and floods. Based on the widely used k-ǫ model for turbulence, we use the techniques of centre manifold theory to derive dynamical models for the evolution of the water depth and of vertically averaged flow velocity and turbulent parameters. This new model for the shallow water dynamics of turbulent flow: resolves the vertical structu...

2006
Carina M. Edwards S. D. Howison H. Ockendon

This paper deals with violent discontinuities in shallow water flows with large Froude number F . On a horizontal base, the paradigm problem is that of the impact of two fluid layers in situations where the flow can be modelled as two smooth regions joined by a singularity in the flow field. Within the framework of shallow water theory we show that, over a certain timescale, this discontinuity ...

Journal: :SIAM J. Scientific Computing 2013
Jed Brown Barry Smith Aron J. Ahmadia

The hydrostatic equations for ice sheet flow offer improved fidelity compared with the shallow ice approximation and shallow stream approximation popular in today’s ice sheet models. Nevertheless, they present a serious bottleneck because they require the solution of a 3D nonlinear system, as opposed to the 2D system present in the shallow stream approximation. This 3D system is posed on high-a...

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