Validation of Open Source CFD for Building External Flows

This paper examines the performance of conventional eddy viscosity and Detached Eddy Simulation (DES) turbulence models implemented in the open source CFD library OpenFOAM. For these purposes we revisit a number of benchmark data sets developed by the Architectural Institute of Japan. We firstly present results for analysis of the flow around a single high rise building and make comparisons with wind tunnel data. Secondly we examine predicted flows in a real urban environment. We find that the eddy viscosity models perform similarly to implementation in other CFD codes. Such modelling approaches give unsatisfactory performance in certain wind conditions, however. The DES results show better prediction of wind flows in comparison to both wind tunnel and field data in many cases.