A steel ball impacting on a bed of very loose, fine sand results in a surprisingly vigorous jet which shoots up from the surface of the sand [D. Lohse, Phys. Rev. Lett. 93, 198003 (2004)10.1103/PhysRevLett.93.198003]. When the ambient pressure p is reduced, the jet is found to be less vigorous [R. Royer, Nature Phys. 1, 164 (2005)10.1038/nphys175]. In this Letter we show that p also affects the...

A height and flow-dependent model for turbulent viscosity is employed to explain the generation of sand waves in tidal seas. This new model resolves the problem of excitation of very long waves in sand wave formation, because it leads to damping of the long waves and gives a finite separation between the most excited mode and the zero mode. For parameters within their physically realistic range...

A simple, quasi-steady, one-dimensional, vertical (1DV) model of unsteady sheet flow is presented. The central aim is to provide greater realism in the near-bed, high-concentration layer, than is possible using models based on the classical referenceconcentration approach. This is achieved by tracking erosion and deposition at the bottom of the mobile sediment layer in relation to the amount of...

the design and optimization of hydrocyclones using cfd techniques are gaining popularity and the key to a successful simulation lies with the accurate description of the high turbulent swirling behavior of the flow. this paper presents a detailed comparison between the omega rsm and the rng k–e turbulence model, which are both derived specially for modeling swirling or rotational flow, in the s...

the objective of this work was to develop a new design of an intake manifold through a 1d simulation. it is quite familiar that a duly designed intake manifold is essential for the optimal performance of an internal combustion engine. air flow inside the intake manifold is one of the important factors, which governs the engine performance and emissions. hence the flow phenomenon inside the inta...

investigating nozzle’s orifice flow is challenging both experimentally and theoretically. this paper focuses on simulating flow inside diesel injector nozzle via ansys fluent v15. validation is performed with experimental results from winkhofler et al (2001). several important parameters such as mass flow rate, velocity profiles and pressure profiles are used for this validation. results includ...

The interplay of gene flow, genetic drift, and local selective pressure is a dynamic process that has been well studied from a theoretical perspective over the last century. Wright and Haldane laid the foundation for expectations under an island-continent model, demonstrating that an island-specific beneficial allele may be maintained locally if the selection coefficient is larger than the rate...