Abstract
Effect of surface roughness on the deposition of particles in a turbulent duct flow is investigated. Instead of the traditional method for roughness modeling (by shifting the interface by a fraction of the roughness standard deviation), direct simulation of rough wall is performed. In this approach, the detail geometry of the rough wall is included in the computational model. A series of computer simulations for various roughness dimensions are performed. An unstructured mesh for the computational domain is generated. Special treatment is taken near the boundaries to achieve good resolution in the near-wall regions. Averaged Navier-Stokes equations are solved by the SIMPLE method, and the Reynolds Stress Transport Model (RSTM) is used to model turbulence stresses. The effects of near wall fluid turbulence fluctuations are examined. Appropriate coefficients for the RSTM model are used to improve the accuracy of the near-wall Reynolds stresses. Lagrangian trajectory analysis method is used for studying particle transport and deposition process. Drag, gravity, and Brownian forces are included in the particle equation of motion. The Brownian force is modeled by a white noise process. The influence of roughness on the particle deposition rate is studied.
Get full access to this article
View all access options for this article.