Aspects of numerical modeling of mixed convection over heated horizontal plate

Abstract

Mixed convection is a common type of heat transfer for relatively slow impinging flows. When fluid flow impinges a transverse flat plate a Hiemenz flow appears. It is basically driven by buoyancy forces, which make it unstable and challenging to simulate. The present study is dedicated to these challenges in terms of computational mesh reduction. Several methods of mesh reduction were tested, including computational domain simplification, symmetry application and mesh coarsening. Each simplification method was tested against experimental data to evaluate proposed hypotheses about symmetry applicability and unconditional advantage of finer meshes. All considered cases were simulated with previously validated numerical model. Although simulated process was seemingly purely symmetrical, it didn’t respond well to implementation of symmetrical boundary conditions. Simplification of computational domain yielded generally expected results showing significant deterioration after truncation of essential part of domain. Mesh coarsening led to erroneous results as well, but dependency wasn’t linear. Statistical analysis proved normality of simulation errors distribution. The present study addresses preprocessing stage of simulation process, providing some insight into simplification methods of computational mesh.