Validation of a Detached Eddy Simulation (DES) Model in Complex Urban Environment

This paper examines the performance of the Detached Eddy Simulation (DES) turbulence model implemented in the open source CFD library OpenFOAM for external flows in complex urban environments. The aim of this work is to provide a validation study of the DES, using an opensource CFD library, in order to make such calculations accessible and affordable. For these purposes we revisit a number of benchmark data sets developed by the Architectural Institute of Japan. We firstly present the results for the analysis of the flow around a single high rise building and make comparisons with wind tunnel data in order to give confidence to the DES implementation. Secondly we examine the prediction capabilities of DES for a flowfield in an actual urban environment, in a sub-central area in Shinjuku Tokyo, where high rise buildings and low rise houses are found close together. Using data derived from wind tunnel experiments and field measurements as well, we conduct the comparison studies and we find that the DES results show significantly better prediction of wind flows in comparison to other approaches.