Hydrodynamic simulation

Tube erosion has been observed in both atmospheric and pressurized bed combustors. The scaling analysis presented earlier can be used to construct an accurate hydrodynamic simulation of the commercial bed. This can be used to qualitatively investigate factors related to tube wear such as the location of highest wear around the circumference of an individual tube and the location within the bed of the tube experiencing the highest wear. Quantitative wear rates cannot be obtained from model tests... 

D Hydrodynamical Simulations of Convection in Red-Giants Stellar Atmospheres... 

Abstract. We present preliminary results of 3D hydrodynamical simulations of surface convection in red giants stars. We investigate the main differences between static ID and 3D time-dependent model stellar atmospheres of red giants for a range of metallicities between solar and [Fe/H] = —3 focusing in particular on the impact of 3D spectral line formation on the derivation of stellar abundances. 

Hydrodynamic simulations of non-linear pulsation for less-massive cooler supergiants have been perfoemed by several authors (Tuchman, Sack and Barkat, 1979 Fadeyev and Tutukov, 1981 Fadeyev, 1982, 1984 Nakata, 1987 Buchler et al., 1987). The outburst of large amplitude pulsation at times is one of common features of these models, and renders mass-loss from the atmosphere of pulsating stars by generating strong shock waves. 

To find out routes of the transition from limit cycles to this type of irregular pulsation, we performed hydrodynamic simulations for a series of models the luminosity log(L/L ) = 3.505, and Te = 5300 Kwith a narrow range of the mass, 1.4 M M 1.5 M by using the hydrodynamic code, TGRID (Simon and Aikawa, 1986). 

The parameters of explosions resulting from our hydrodynamic simulations have been extensively reported. Confirmation of these results are seen in the recent work of Bruenn [23], some of which is as yet unpublished. A key component of any such calculations is the (- -transport scheme which in our calculations has only recently been carried out in complete detail to the level found in Bruenn [23] or Wilson and Mayle [15]. 

Yang, J., Li, C.W., Yang, M.S., Hydrodynamic simulation of cell docking in microfluidic channels with different dam structures. Labchip 2004, 4, 53-59. 

Hence the missing baryons could be in the WHIM, which would be correspondingly enriched. Unfortunately such strong winds are not supported by hydrodynamical simulations. These use supernovae as the energy source that drives the wind. However the current multiphase simulations lack sufficient fine-scale resolution, as discussed below. 

However numerical simulations of early supernova-driven winds fail to find any evidence for substantial gas ejection from luminous ( L ) galaxies. One can ask what is wrong with the hydrodynamic simulations Certainly, the simulations lack adequate resolution. Rayleigh-Taylor instabilities enhance wind porosity and Kelvin-Helmholtz instabilities enhance wind loading of the cold interstellar medium. Both effects are certain to occur and will enhance the wind efficacity. Yet another omission is that one cannot yet resolve the motions of massive stars before they explode. This means that energy quenching is problematic and the current results are inconclusive for typical massive galaxies. 

The experimental results were analyzed using an integrated approach. To obtain the temporal evolution of the temperature and the density profiles of the bulk plasma, the experimental hot-electron temperature was used as an initial condition for the 1D-FP code [26]. The number of hot electrons in the distribution function were adjusted according to the assumed laser absorption. The FP code is coupled to the 1-D radiation hydrodynamic simulation ILESTA [27]. The electron (or ion) heating rate from hot electrons is first calculated by the Fokker-Planck transport model and is then added to the energy equation for the electrons (or ions) in ILESTA-1D. Results were then used to drive an atomic kinetics package [28] to obtain the temporal evolution of the Ka lines from partially ionized Cl ions. 

To evaluate the heating, a relativistic 1-D Fokker-Planck code was used. The configuration space is 1-D but the momentum space is 2-D, with axial symmetry. This code is coupled to a radiation-hydrodynamic simulation in order to include energy dissipation via ionization processes, hydrodynamic flow, the equation-of-state (EOS), and radiation transport. The loss of kinetic energy from hot electrons is treated through Coulomb and electromagnetic fields. 

The radiation-hydrodynamic simulation includes the Quotidien EOS [29] and Ion EOS based on the Cowan model [30], For the electron component, a set of fitting formulae derived from the numerical results from the Thomas-Fermi model and a semi-empirical bonding correction [31] are adopted. The effective Z-number of the partially ionized plasma is obtained from the average atom model. Radiation transport is treated by multigroup diffusion. 

The giant planets ceased growing when the flow of gas onto their envelopes was cut off. This may have been the result of gap formation or because the nebula dispersed. The latter seems unlikely, since the timescale for gas accretion onto a Jupiter-size planet is small compared to the lifetime of the nebula. However, hydrodynamical simulations suggest that gas would continue to flow onto Jupiter after it cleared a gap in the disk (Lubow et al., 1999), so this explanation is problematical too. In addition, it has been suggested that some gas would remain at the same orbital distance as the planet after it cleared a gap if the disk viscosity was low (Rafikov, 2002), and this would also be accreted by the planet eventually. 

Pfleger, D., Gomes, S., Gilbert, N. and Wagner, H.-G. (1999), Hydrodynamic simulations of laboratory scale bubble columns fundamental studies of the Eulerian-Eulerian modeling approach, Chem. Eng. Sci., 54, 5091-5099. 

Wu, Y. and Gidaspow, D. (2000), Hydrodynamic simulation of methanol synthesis in gas-liquid slurry bubble column reactors, Chem. Eng. Sci., 55, 573-587. 

Guardo, M., and Tomasello, R. (1995) Hydrodynamic simulations of a constructed wetlands in South Florida, Water Resources Bulletin 31, 687-701. 

Figure 2. Suppression of identical particle collisions. Full squares measured scattering cross-section for Beliaev damping as a function of the excitation wavenumber in units of the inverse healing length. The assumptions of our analysis are tested using hydrodynamic simulations (dashed line), and found to agree with Beliaev damping theory (solid line) and the experimental data. Corrections observed in the hydrodynamic simulation take into account the full inhomogeneity and finite size of the experimental system, and validate the approximations of our analysis.

In order to study the decoherence of quasi-particles within BEC, we use Bragg spectroscopy and Monte Carlo hydrodynamic simulations of the system [Castin 1996], and confirm recent theoretical predictions of the identical particle collision cross-section within a Bose-Einstein condensate. We use computerized tomography [Ozeri 2002] of the experimental images in determining the exact distributions. We then conduct both quantum mechanical and hydrodynamic simulation of the expansion dynamics, to model the distribution of the atoms, and compare theory and experiment [Katz 2002] (see Fig. 2). 

A second consequence is that the outflow which occurs due to a star hitting the 12-limit, is predicted to be highly bipolar. This is illustrated by a hydrodynamical simulation of the giant eruption of r] Car by Langer el al. (1999). The fact that virtually all LBV nebulae are highly bipolar supports the idea that the D-limit is actually involved in the LBV instability. 

Fig. 2. The results of a hydrodynamic simulation showing an explosion (taken from [7])...

A BKW equation of state in a one-dimensional hydrodynamic simulation of the cylinder test can be used to estimate the performance of explosives. Using this approach, the novel explosive 3,6-diamino-l,2,5,6-tetrazine 1,4-dioxide has been analyzed . 

Figure 6.5 Hydrodynamic simulation of methanol synthesis in gas-Uquid slurry bubble column reactors, (a) Reactor operating conditions and simulation grid, (b) Simulated instantaneous distribution of gas and solid holdup, (c) Simulated instantaneous distribution of temperature.

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