Search results for "hydrodynamic"
showing 10 items of 530 documents
Study of thermoelectric magnetohydrodynamic convection on solute redistribution during laser additive manufacturing
2020
Abstract Melt pools formed in laser additive manufacturing (AM) are subject to large thermal gradients, resulting in the formation of thermoelectric currents due to the Seebeck effect. When in the presence of an external magnetic field, a Lorentz force is formed which drives fluid flow in the melt pool. This Thermoelectric Magnetohydrodynamics (TEMHD) phenomenon, can have a significant impact on the melt pool morphology and can alter the microstructural evolution of the solidification process. By coupling steady-state mesoscopic melt pool calculations to a microscopic solidification model, predictions of the resulting microstructure for multiple deposited layers have been obtained. The resu…
Three-dimensional core-collapse supernovae with complex magnetic structures: I. Explosion dynamics
2021
Magnetic fields can play a major role in the dynamics of outstanding explosions associated to violent events such as GRBs and hypernovae, since they provide a natural mechanism to harness the rotational energy of the central proto-neutron star and power relativistic jets through the stellar progenitor. As the structure of such fields is quite uncertain, most numerical models of MHD-driven core-collapse supernovae consider an aligned dipole as initial magnetic field, while the field's morphology can actually be much more complex. We present three-dimensional simulations of core-collapse supernovae with more realistic magnetic structures, such as quadrupolar fields and, for the first time, an…
The impact of non-dipolar magnetic fields in core-collapse supernovae
2019
The magnetic field is believed to play an important role in at least some core-collapse supernovae if its magnitude reaches $10^{15}\,\rm{G}$, which is a typical value for a magnetar. In the presence of fast rotation, such a strong magnetic field can drive powerful jet-like explosions if it has the large-scale coherence of a dipole. The topology of the magnetic field is, however, probably much more complex with strong multipolar and small-scale components and the consequences for the explosion are so far unclear. We investigate the effects of the magnetic field topology on the dynamics of core-collapse supernovae and the properties of forming proto-neutron star (PNS) by comparing pre-collap…
Parametric sensitivity of a CFD model concerning the hydrodynamics of trickle-bed reactor (TBR)
2016
Abstract The aim of the present study was to investigate the sensitivity of a multiphase Eulerian CFD model with respect to relations defining drag forces between phases. The mean relative error as well as standard deviation of experimental and computed values of pressure gradient and average liquid holdup were used as validation criteria of the model. Comparative basis for simulations was our own data-base obtained in experiments carried out in a TBR operating at a co-current downward gas and liquid flow. Estimated errors showed that the classical equations of Attou et al. (1999) defining the friction factors Fjk approximate experimental values of hydrodynamic parameters with the best agre…
Univariate and multivariate properties of wind velocity time series
2009
We analyze the time series of hourly average wind speeds measured at 29 different stations located in Sicily, a region with a complex morphology. The investigation, performed from the univariate as well as the multivariate point of view, evidences that the statistical properties of wind at the single sites have features that are not reproduced by standard models and, thus, require specific modeling. Moreover, the synchronous evolution of wind velocity presents a cluster structure, obtained with different algorithms, that persists in the standard deviation too.
Wind- and tide-induce currents in the Stagnone Lagoon (Sicily)
2009
Разработка и применение специальных численных методов для решения задач математической физики, гидродинамики и магнитной гидродинамики
1993
Прикладные задачи математической физики: Математическое моделирование
1990
Настоящий сборник содержит работы по математическому моделированию различных физических и технологических процессов. Анализируются процессы тепло- и массопереноса в расплавах и жидкостях, задачи термоупругости и упругопластического деформирования в кристаллах.
Прикладные задачи математической физики: Математическое моделирование
1991
Сборник содержит работы, посвященные математическому моделированию различных физических и технологических процессов. Анализируются процессы тепло- и массопереноса в расплавах и жидкостях, задачи термоупругости и упругопластического деформирования в кристаллах.