Numerical simulations of natural convection performed with the usual Boussinesq equations result in unbalanced irreversibility budget. The thermodynamic Boussinesq equations solve this problem, especially because they simulate production of kinetic energy within the fluid through its expansion and contraction. These fluid volume changes, without which natural convection would not occur, also induce heat transfer by piston effect. The piston effect, which appears then as an intrinsic component of buoyancy-induced natural convection, introduces the non-dimensional adiabatic temperature gradient as a control parameter of natural convection.
Les simulations numériques réalisées avec les équations de Boussinesq usuelles ne peuvent pas donner un bilan d'irréversibilité fermé. Les équations de Boussinesq thermodynamiques apportent une solution au problème, en particulier parce qu'elles incluent la production d'énergie cinétique à l'intérieur du fluide, par sa dilatation et contraction. Ces variations de volume du fluide, sans lesquelles la convection naturelle n'existerait pas, provoquent aussi un transfert de chaleur par effet piston. L'effet piston, qui apparaît alors consubstantiel à la convection naturelle, fait du gradient de température adiabatique adimensionné un des paramètres de contrôle de la convection naturelle.
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Mots-clés : Transferts thermiques, Mécanique des fluides, Convection naturelle, Boussinesq, Thermodynamique, Irréversibilités, Effet piston
Michel Pons 1; Patrick Le Quéré 1
@article{CRMECA_2005__333_2_133_0, author = {Michel Pons and Patrick Le Qu\'er\'e}, title = {An example of entropy balance in natural convection, {Part} 2: the \protect\emph{thermodynamic} {Boussinesq} equations}, journal = {Comptes Rendus. M\'ecanique}, pages = {133--138}, publisher = {Elsevier}, volume = {333}, number = {2}, year = {2005}, doi = {10.1016/j.crme.2004.11.003}, language = {en}, }
TY - JOUR AU - Michel Pons AU - Patrick Le Quéré TI - An example of entropy balance in natural convection, Part 2: the thermodynamic Boussinesq equations JO - Comptes Rendus. Mécanique PY - 2005 SP - 133 EP - 138 VL - 333 IS - 2 PB - Elsevier DO - 10.1016/j.crme.2004.11.003 LA - en ID - CRMECA_2005__333_2_133_0 ER -
Michel Pons; Patrick Le Quéré. An example of entropy balance in natural convection, Part 2: the thermodynamic Boussinesq equations. Comptes Rendus. Mécanique, Volume 333 (2005) no. 2, pp. 133-138. doi : 10.1016/j.crme.2004.11.003. https://comptes-rendus.academie-sciences.fr/mecanique/articles/10.1016/j.crme.2004.11.003/
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