Effective surface and boundary conditions for heterogeneous surfaces with mixed boundary conditions

JOURNAL OF COMPUTATIONAL PHYSICS

卷:305

Article

Guo, Jianwei¹  Veran-Tissoires, Stephanie^1,2  Quintard, Michel^1,3 

[1] Univ Toulouse, IMFT, INPT, UPS, F-31400 Toulouse, France

[2] Tufts Univ, Dept Civil & Environm Engn, Medford, MA 02155 USA

[3] CNRS, IMFT, F-31400 Toulouse, France

关键词: Heterogeneous surface;    Multi-domain decomposition;    Closure problems;    Effective surface;    Effective boundary conditions;   

DOI  :  10.1016/j.jcp.2015.10.050

来源: Elsevier

【 摘 要 】

To deal with multi-scale problems involving transport from a heterogeneous and rough surface characterized by a mixed boundary condition, an effective surface theory is developed, which replaces the original surface by a homogeneous and smooth surface with specific boundary conditions. A typical example corresponds to a laminar flow over a soluble salt medium which contains insoluble material. To develop the concept of effective surface, a multi-domain decomposition approach is applied. In this framework, velocity and concentration at micro-scale are estimated with an asymptotic expansion of deviation terms with respect to macro-scale velocity and concentration fields. Closure problems for the deviations are obtained and used to define the effective surface position and the related boundary conditions. The evolution of some effective properties and the impact of surface geometry, Peclet, Schmidt and Damkohler numbers are investigated. Finally, comparisons are made between the numerical results obtained with the effective models and those from direct numerical simulations with the original rough surface, for two kinds of configurations. (C) 2015 Elsevier Inc. All rights reserved.

【 授权许可】

Free