Sávio Vianna is a chemical engineer and professor at the University of Campinas (Unicamp) in Brazil. His main research area concerns the investigation of computational modelling of reacting and non-reacting flows. By dealing with the latest numerical schemes and available open sources tools, as well as in house codes, Dr. Vianna has been trying to reinforce the bridge between basic science and the engineering of fluid flow. He is also interested in the application of laser techniques, such as PIV (Particle Image Velocimetry) and LES (Large Eddy Simulation) for turbulent combustion.
The small scale geometry is of paramount importance when modelling reacting flows. As the reacting front propagates it generates the flow ahead of it which interact with small objects, generating a turbulent field. This process enhances the mixture among the reactants leading to a more efficient reaction. The whole process acts as a positive feedback mechanism. However, it is not always that the details of the geometry can be solved within the scale of the mesh size. Mainly due to the design timeline constrains and computational resources.
Alternatively, the geometry can be modelled based on the concept of porosity. The side figure is an example of the parametrisation of the geometry using the collision between two convex objects using the Minkowiski addition. In such approach, the flow through regions of the computational domain vanishes where the porosity is zero.