We study the initial instability of flat sand surface and further nonlinear dynamics of wind ripples. The proposed continuous model of ripple formation allowed us to simulate the development of a typical asymmetric ripple shape and the evolution of a sand ripple pattern. We suggest that this evolution occurs via ripple merger preceded by several soliton-like interaction of ripples.

The transport characteristics of iron nanoparticles prepared with a green tea, polyphenol-rich solution, were investigated for two granular media, pure silica sand and sand coated with aluminium hydroxide. The GT-nZVI injection caused a sharp decrease in the effluent pH and increase in the redox potential, which is attributed to the presence of free Fe and polyphenols in the suspension, respect...

in this research, the effect of friction between the liquid metal and the sand mould wall and the effect of passage of liquid through a vertical bend and through a ceramic filter on the fluid flow and the melt velocity has been studied by measuring the velocity of the melt and direct observation of the liquid flow through the different parts of a naturally-pressurized running system. the fricti...

Collection of storm water runoff and forcing it into the groundwater is the need of the hour to sustain the ground water table. However, the runoff entraps various types of sediments and other floating objects whose removal are essential to avoid pollution of ground water and blocking of pores of aquifer. However, it requires regular cleaning and maintenance due to problem of clogging. To evalu...

This paper reports on an experimental study on the ploughing or orthogonal cutting in sand. Plane strain cutting or ploughing experiments were carried out on model Ottawa sand while being imaged at high resolution. The images obtained were further processed using image analysis and the evolution of the velocity and deformation fields were obtained from these analysis. The deformation fields sho...

Waste water was collected from the municipal town of Madurai and was subjected to filtration in two different filters. The first filter employed sand for the process of filtration where as the second filter carbon for the same. Finally when the clarified water is drawn out of the filter, it shows that there is a considerable reduction in the physico-chemical parameters then that of the untreate...

Offshore activities often encounter large scale sand patterns, such as sand waves. Sand waves are offshore bed forms occurring at water depths of 10 to 50 m. Their wavelengths can lead up to 500 m and their heights are typically several metres. Furthermore, sand waves have been shown to migrate, with typical velocities of up to metres per year. These dynamic sand waves decrease the least naviga...

slow sand filtration (s.s.f) is a main process in the water treatment technology and generally considered as most appropriate for application in rural and small urban areas in developing countries. however, performance of the s.s.f is very sensitive to high turbidity levels. therefore, pretreatment is necessary for such waters. horizontal - flow roughing filtration (hfrf) and direct horizontal ...