Interpenetration Of Fluids Research Articles

Computational fluid dynamics analysis for smart control of water supply

Abstract This work investigated the partition walls or baffles’ effects on hydraulic parameters and water retention time in a reservoir. According to this aim, the water system was equipped with remote sensing (RS), networked sensors, advanced modems, and data loggers. The study showed how to control hydraulic parameters by the Internet of things and RS. The higher retention time led to the probability growth of rebar oxidation in concrete in the presence of chlorine and increased the possibility of water loss. This work also showed how to decrease the probability of water leakage in reservoirs. The computational fluid dynamics analysis results showed that the two baffles case led to the emergence of three eddy currents in the three zones created. The better fluid interpenetration caused the reduction in retention time. In the areas where the vortex was formed, the number of eddy currents decreased and the retention time increased. Regression analysis showed that the P value was 0.998 and 0.977 for the inlet flow and outlet flow for the reservoir, respectively (two baffles case perpendicular to the flow direction). The curve estimation showed that the power function had a suitable correlation on the scatter diagram and with the best curve fit.

Experimental investigation into the self-similar mode of mixing of different density gases in the Earth's gravitational field

Experiments on self-similar Rayleigh–Taylor instability-induced mixing in gases in the Earth's gravity conducted on the OSA facility at the Russian Federal Nuclear Center–VNIITF are described. These experiments are distinguished from other experiments, usually performed with immiscible liquids in a tank or with miscible liquids initially separated by a solid barrier that is retracted, in that a membrane (of ∼1 μm thickness) with liquid soap film embedded in a thin wire array (with microconductors of diameter 20 μm and with a spacing of 4 mm) initially separates the fluids. An electric current to initiate the fluid interpenetration and mixing destroys the membrane. Experiments performed for three different Atwood numbers are described: in SF6-Ar with A = 0.54, in SF6-He with A = 0.94, and in Kr-Ar with A = 0.35. Various parameters of the mixing were measured from Schlieren photographs. In particular, the dimensionless rate of mixing front growth is α = 0.078.

Two-point description of two-fluid turbulent mixing—I. Model formulation

We describe a two-point spectral transport approach to the investigation of fluid instability, generalized turbulence, and the interpenetration of fluids across an interface. The technique also applies to a single fluid with large variations in density. Departures of fluctuating velocity components from the local mean are far subsonic, but the mean Mach number can be large. This work is focused on flows with large variations in fluid density (e.g. two-field fluid interpenetration). The starting point for analysis is the set of Navier–Stokes equations, for which we assume relevance in our investigations, even in the presence of sharp density variations between fluids. Models for two-field analysis with drag representations for momentum exchange can also be used and are discussed previously. In this work departures from mean flow are included in the stochastic concept of turbulence. Reynolds decomposition into mean and fluctuating parts is carried out in the spirit of this generalized concept, which is meaningful despite arbitrariness as to which scales are identified as mean flow and which are identified as fluctuations. This spectral formulation motivates a novel description of the global effects of pressure due to incompressibility. We discuss its derivation and the modifications this ‘nonlocal’ formulation has on the turbulence spectra. We also discuss the consequences of spectral self-similarity exhibited by this model. This identification of spectral self-similarity in a circumstance of inhomogeneous, variable density turbulence is novel.