Comparison between Dirichlet-Robin and Neumann-Robin Interface Conditions in CHT Problems

R. Moretti (1) , Marc Errera (1)

1 DAAA, ONERA, Université Paris-Saclay (COmUE) [Châtillon]

± This paper presents and compares the stability and the performance of two different boundary conditions in steady conjugate heat transfer (CHT) problems. The Dirichlet-Robin interface and the Neumann-Robin interface condition have been implemented. The choice between the two interface conditions depends on the numerical Biot number that is a local representation of the thermal fluid-structure interaction and plays a key role in the stability of the coupling process. The coupling coefficient of the Robin condition is determined by the transition of the amplification factor derived from a normal mode stability analysis based on the Godunov-Ryabenkii theory. A study of an academic 2D test case illustrates that, although the Dirichlet-Robin interface condition is optimal for low and moderate thermal fluid-structure interaction, the Neumann-Robin condition is a relevant choice at higher thermal fluid-structure interaction.

Mots clés: CHT; Neumann; Dirichlet; Robin; Stability; Optimal Coefficient; Biot Number; Boundary Condition

Domaines: Physique mathématique [math-ph]; Mécanique des fluides [physics.class-ph]; Mécanique des solides [physics.class-ph]; Thermique [physics.class-ph]

R. Moretti, Marc Errera. Comparison between Dirichlet-Robin and Neumann-Robin Interface Conditions in CHT Problems. 5th International Conference of Fluid Flow, Heat and Mass Transfer (FFHMT'18), Jun 2018, Niagara Falls, Canada. ⟨10.11159/ffhmt18.112⟩. ⟨hal-01843494⟩