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Whole field formulation

The derivation of the given whole field formulation, introducing the Dirac delta function (d/) into the surface tension force relation to maintain the discontinuous (singular) nature of this term, is to a certain extent based on physical intuition rather than first principles (i.e., in mathematical terms this approach is strictly not characterized as a continuum formulation on the differential form). Chandrasekhar [31] (pp 430-433) derived a similar model formulation and argued that to some extent the whole field momentum equation can be obtained by a formal mathematical procedure. However, the fact that the equation involves /-functions means that to interpret the equation correctly at a point of discontinuity, we must integrate the equation, across the interface, over an infinitesimal volume element including the discontinuity. [Pg.350]

In addition, we need to specify which quantities are continuous and which bounded at an interface between two fluids. Similar whole field formulations have been used and further discussed by Lafaurie et al. [132], Sussman et ah [214], Chang et al. [32], Popinet and Zaleski [164], Gue3dEer et al. [92] and Tryggvason [222] [183]. [Pg.351]

The momentum equations in the whole field formulation can also be rewritten in a momentum conserving form [132] [183] [92], defining a 3D capillary pressure tensor... [Pg.354]

In this section the basis elements of the volume of fluid (VOF) method are described. In general the VOF model is composed of a set of continuity and momentum equations, as well as a transport equation for the evolution of a phase indicator function which is used to determine the location and orientation of the interface. We distinguish between the jump condition—and the whole field formulations of the method, in which both forms are based on a macroscopic view defining the interface as a 2D surface. The jump condition form is especially convenient for free-surface flow simulations, whereas the whole field formulation is commonly used for interfacial flow calculations in which the internal flow of all the phases are of interest. [Pg.380]

In this section the embedded interface (El) method (frequently referred to as a front tracking method) developed for direct numerical simulations of viscous multi-fluid flows is outlined and discussed. The unsteady model is based on the whole field formulation in which a sharp interface separates immiscible fluids, thus the different phases are treated as one fluid with variable material properties. Therefore, Eqs. (3.14) and (3.15) account for both the differences in the material properties of the different phases as well as surface tension effects at the phase boundary. The bulk fluids are... [Pg.394]

One of the least well understood aspects of the whole field is the precise physical nature of the process whereby polymer chains of a different size are separated by passage through a gel column. On a qualitative level adec[uate explanations of the phenomenon exist but it has proved to be a more difficult task to formulate and solve anything other thcui the simplest of mathematical models of the chromatographic process. [Pg.25]

The nonlocal dielectric theory has as a special case the standard local theory. Its fuller formulation permits the introduction in a natural way of statistical concepts, such as the correlation length which enters as a basic parameter in the susceptibility kernel For brevity we do not cite many other features making this approach quite useful for the whole field of material systems, not only for solutions. [Pg.13]

In fact it is possible to show in a Bayesian formulation that if some prior doubt is allowed that the trial may not be competent to find a difference, then although, conditional upon a belief in competence, the posterior probability of equivalence will rise the more patients are studied and the more that prognosis is found to be the same in the two groups, the more the posterior belief must increase that the trial is not competent to find a difference (Senn, 1993). In short, the whole field is summed up by the oxymoron equivalence is different . [Pg.239]

A special tribute is due to Dr. Charles Starks of the Continental Oil Company. By the mid sixties, Starks had formulated the principles of phase transfer catalysis and had applied for patents on many reactions that others were later to examine in somewhat greater detail. His mechanistic model of phase transfer catalysis still stands up well today and is a model for much of the thinking in this area. It is fitting that Starks suggested the name phase transfer catalysis by which the whole field is now known. [Pg.287]

The principle of precaution was formulated for the first time in the Rio Declaration in 1992, and initially only applied to environmental risks. It was rapidly extended to the whole field of major medical risks. For example, read GoUier [11], or Guilhou [12]. [Pg.114]

The salient features of quantum formulation of Onsager reaction field model (dipole model) is described here. In this method, the reaction field is treated as perturbation to the Hamiltonian of the isolated molecule. If H0 is the Hamiltonian of the isolated molecule and HR[ is the reaction field [21], the Hamiltonian of the whole system (Hlol) is represented as... [Pg.384]

Field Pea Flour in Other Baked Products. When McWatters (44) substituted 8% field pea flour and 4.6% field pea concentrate for milk protein (6%) in baking powder biscuits, sensory attributes, crumb color, and density of the resulting biscuits were adversely affected. No modifications were made in recipe formulation when pea products were incorporated. The doughs were slightly less sticky than control biscuits that contained whole milk. This might be due to lack of lactose or to the different water absorption properties of pea protein or starch. Panelists described the aroma and flavor of these biscuits as harsh, beany and strong. Steam heating the field pea flour improved the sensory evaluation scores, but they were never equivalent to those for the controls. [Pg.32]

The effects of the nonylphenol in the Matacil 1.8D OSC formulation give greatest cause for concern. At a concentration of 1.1 pig/ml that has been found in the field (40), nonylphenol can significantly delay the growth of a population of Chlorella pyrenoidosa, where swathe overspray occurs, concentrations may be obtained that could kill the whole population of exposed cells (20). Delays in population growth in Chlamydomonas reinhardtii and Chlorella vulgaris was also observed after treatment with Aerotex (10). [Pg.361]


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See also in sourсe #XX -- [ Pg.344 , Pg.350 ]




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