A variational solution to the transient heat flow measure above a closed conductive region of arbitrary perimeter aspect, held at constant temperature, and which is embedded in an otherwise insulating boundary plane, is presented. Upon developing the general variational formulation, a full range solution for the circular disk conductor is considered as an example when implementing a two term trial function that comprises a general form based on known physical solutions to the problem at long and short times. The particular combination of the Lagrange density for the total transient diffusive flux and of the form of the trial functions are evidently effective in dealing with the difficulties often experienced when dealing with mixed boundary value heat transfer problems of the parabolic type which have a non-periodic time variable.
Une solution variationnelle à la mesure du flux thermique transitoire au-dessus d’une région conductrice fermée d’aspect de périmètre arbitraire, maintenue à température constante, et qui est encastrée dans un plan limite autrement isolant, est présentée. Après avoir développé la formulation variationnelle générale, une solution complète pour le conducteur en forme de disque circulaire est considérée comme un exemple lors de la mise en œuvre d’une fonction d’essai à deux termes qui comprend une forme générale basée sur des solutions physiques connues du problème à des temps longs et courts. La combinaison particulière de la densité de Lagrange pour le flux diffusif transitoire total et de la forme des fonctions d’essai est évidemment efficace pour traiter les difficultés souvent rencontrées lors du traitement des problèmes de transfert de chaleur à valeur limite mixte de type parabolique qui ont une variable temporelle non périodique.
Accepted:
Published online:
Mots-clés : Solution variationnelle, conducteur incorporé, condition limite mixte, équation de la chaleur, disque circulaire
William Pons 1; Stanley Pons 2, 3
@article{CRMECA_2023__351_G2_247_0, author = {William Pons and Stanley Pons}, title = {A {Variational} {Calculation} of {Diffusive} {Flux} in a {Mixed} {Boundary} {Value} {Problem}}, journal = {Comptes Rendus. M\'ecanique}, pages = {247--263}, publisher = {Acad\'emie des sciences, Paris}, volume = {351}, year = {2023}, doi = {10.5802/crmeca.198}, language = {en}, }
William Pons; Stanley Pons. A Variational Calculation of Diffusive Flux in a Mixed Boundary Value Problem. Comptes Rendus. Mécanique, Volume 351 (2023), pp. 247-263. doi : 10.5802/crmeca.198. https://comptes-rendus.academie-sciences.fr/mecanique/articles/10.5802/crmeca.198/
[1] Methods of Theoretical Physics, 1-2, McGraw-Hill Book Co., 1953 | MR | Zbl
[2] On the Theory of Diffraction by an Aperture in an Infinite Plane Screen. I, Phys. Rev., Volume 74 (1948) no. 8, pp. 958-974 | DOI | Zbl
[3] Sur un problème mixte relatif à l’équation de Laplace, Bulletin de l’Académie des sciences de Cracovie, Classe des sciences mathématiques et naturelles, serie A (1910), pp. 313-344 | Zbl
[4] A New Theory of Potential Step Chronoamperometry at a Microdisk Electrode: Complete Explicit Semi-Analytical Formulae for the Faradaic Current Density and the Faradaic Current, Electrochim. Acta, Volume 199 (2016), pp. 1-11 | DOI
[5] Highly accurate, inexpensive procedures for computing chronoamperometric current, integral transformation kernel, and related integrals, for an inlaid disk electrode, Electrochim. Acta, Volume 259 (2018), pp. 1068-1080 | DOI
[6] Diffusion-Controlled Chronoamperometry at a Disk Electrode, Anal. Chem., Volume 77 (2005) no. 18, pp. 6100-6101 (PMID: 16159148) | DOI
[7] Formulation of the diffusion-controlled current at very small stationary disk electrodes, J. Electroanal. Chem., Volume 160 (1984) no. 1, pp. 335-339 | DOI
[8] Chronoamperometric current at finite disk electrodes, J. Electroanal. Chem., Volume 140 (1982) no. 2, pp. 237-245 | DOI
[9] A two-point Padé approximation for the non-steady-state chronoamperometric current at ultramicrodisc electrodes, J. Electroanal. Chem., Volume 392 (1995) no. 1, pp. 75-78 | DOI
[10] Diffusion at ultramicroelectrodes: chronoamperometric current response using Padé approximation, J. Phys. Chem. B, Volume 101 (1997), p. 4583 | DOI
[11] Diffusion at Ultramicro Disk Electrodes: Chronoamperometric Current for Steady-State Ec‘ Reaction Using Scattering Analogue Techniques, J. Phys. Chem. B, Volume 103 (1999) no. 9, pp. 1518-1524 | DOI
[12] The short-time transient of diffusion outside a conducting body, Proc. R. Soc. Lond., Ser. A, Volume 428 (1990) no. 1875, pp. 431-449 | DOI | Zbl
[13] Compact and accurate approximants to determine the transient current at the disc electrode under different boundary conditions, Electrochim. Acta, Volume 56 (2011) no. 7, pp. 2877-2880 | DOI
[14] Digital Simulation in Electrochemistry, 1, Springer, 2016 | DOI
[15] Average Surface Temperature Over the Circular Disk Heat Source/Sink Embedded in an Insulating Boundary Plane. Analytic Solution., C. R. Méc. Acad. Sci. Paris, Volume 351 (2023), pp. 17-27 | DOI
[16] The plasma dispersion function: the Hilbert transform of the Gaussian, Academic Press Inc., 1961, 426 pages
Cited by Sources:
Comments - Policy