Numerical simulations of turbulent flows using high performance computing

Abstract

This report presents the procedures and results obtained in the project ’Numerical Simulation of Turbulent Flows Using High Performance Computing’, in which a high performance code for fluid dynamics simulation (SA3) has been extended. Firstly, sub-mesh modelling has been incorporated into the integration of the Navier-Stokes equations using a source term representative of the turbulent transport. This operator has been generalized for any field, its discretization has been implemented and it has been validated by means of the Method of Manufactured Solutions (MMS). The problem is closed by a sub-mesh viscosity calculated by Smagorinsky, WALE and Vreman models. In addition, their boundary conditions have been carefully analysed. These models have also been successfully validated using the MMS method. Finally, the effect of the sub-mesh viscosity on the Courant-FriederichLewis condition has been added for the estimation of the maximum time step, completing the extension of SA3 for the execution of Large-Eddie Simulations (LES). In the second place, the solutions obtained for the case of a Channel Flow are studied, analyzing the capacity of the code to resolve turbulent flows and boundary layers. Therefore, the statistical description of the turbulent flow and the algorithms to calculate its different parameters are presented. Next, a scalability analysis is carried out according to the density of the mesh used, and the profiles of the statistical parameters obtained without using a turbulence model are compared with the profiles obtained using the Vreman and WALE models. Based on the results obtained throughout the project, the conclusions obtained and future recommendations are finally presented