+ Translate

Transport by advection and diffusion revisited

, : Transport by advection and diffusion revisited. Vadose zone journal VZJ 2(4)

Mass transport by advection and diffusion is involved in nearly all branches of science, but various scientific disciplines define the two mechanisms of transport differently. Models widely accepted for combining transport resulting from advection and diffusion are shown to be inconsistent with experimental observations. Experimental observations are cited to show that the barycentric velocity of a solution is not synonymous with velocity as determined by the Navier-Stokes equation of fluid motion. The physics of advection and diffusion is analyzed, and requirements for combining advection and diffusion are presented. Advection is defined here as transport responding to a pressure gradient or body force. Molecular diffusion is defined as transport responding to concentration or thermal gradients. Diffusion represents an average velocity component of molecules of a particular constituent relative to a fixed frame of reference external to the solution, rather than to the mean velocity of all constituents in a solution as defined in current literature. Advection and diffusion contribute independently to the total transport.

Accession: 004371781

PDF Full Text: Submit

Submit PDF Full Text

No spam - Every submission is manually reviewed

Due to poor quality, we do not accept files from Researchgate

Submitted PDF Full Texts will always be free for everyone
(We only charge for PDFs that we need to acquire)

Select a PDF file:

Other references

Morel, Pc, 1978: Wild animal ticks in Upper Volta. Revue d'elevage et de medecine veterinaire des pays tropicaux: new ser) 31 (1) 69-78

Anonymous, 1979: Regional seminar on the use and management of pesticides in Central America, Guatemala, Central America, June 1978. This volume contains the papers that were read at a conference held in Guatemala from 26 to 30 June 1978 on the use and management of pesticides (especially insecticides and acaricides used for the control of pests of agricultural, medical or vete...

Nonoyama, T.; Tatsumi, J.; Izawa, T.; Taneda, Y., 1988: Physiological and ecological characteristics of high-yielding rice varieties and their cultivation method. I. Dry matter production and translocation of carbohydrate. The vertical distribution and changes in DW of each part of the indica rice cv. Raikei, Suweon 258 and Hokuriku and the japonica cv. Koganebare were studied. In the semi-dwarf indica cultivars the annual rate of increase of panicle DW/unit area wa...

Ezagouri, Meital; Yom-Din, Svetlana; Goldberg, Doron; Jackson, Karen; Levavi-Sivan, Berta; Degani, Gad, 2008: Expression of the two cytochrome P450 aromatase genes in the male and female blue gourami Trichogaster trichopterus during the reproductive cycle. In this study, the involvement of the cytochrome P450 aromatase gene (CYP19) in the gametogenesis of the teleost blue gourami (Trichogaster trichopterus) is described. The blue gourami brain CYP19 (bgCYP19b) and gonadal CYP19 (bgCYP19a) aromatase...

Johnson, C.W., 1929: The egg-capsules of Fasciolaria giyantea Kiener. Nautilus Philad3: 63

Montalescot, Gilles; Choussat, Remi; Philippe, Francois; Collet, Jean Philippe; Ankri, Annick; Drobinski, Gerard; Thomas, Daniel, 1999: Both PE-hirudin and enoxaparin blunt the rise of von Willebrand factor in patients with unstable angina. Journal of the American College of Cardiology 33(2 SUPPL A): 351A-352A, Feb

Parker, Gr; Leopold, Dj, 1983: Replacement of Ulmus americana L. in a mature east-central Indiana woods. Bulletin of the Torrey Botanical Club 110(4): 482-488

Anonymous, 2013: Concepto de insuficiencia cardiaca. Su clasificaci n, fisiopatolog a y etiolog a. La insuficiencia cardiaca se define como la incapacidad del coraz n para suministrar ox geno a una frecuencia acorde con las necesidades. Sus causas y desencadenantes son m ltiples, pero las m s frecue...

Tuchy, Gerhard L.; Tuchy, Eveline; Calava, Jeffry M.; Smith, L. Gary; Welch, Gary W., 1994: Pharmacodynamics of mivacurium chloride administered at full recovery from succinylcholine chloride. Anesthesia & Analgesia 78(2 SUPPL ): ABSTRACT S442

Crisp, Ah; Hall, A; Holland, Aj, 1985: Nature and nurture in anorexia nervosa: A Study of 34 pairs of twins, one pair of triplets, and an adoptive family. This paper reports observations following on a study of anorexia nervosa in 34 twins and one set of triplets, and within which approximately half the monozygotic (MZ) twins displayed concordance, compared with 7% of the dizygotic (DZ) twins. One...