Uncertainty in Measurements of Velocity and Concentration around a Building

As with the progress of computing capacity in recent years, there have been many CFD studies concerned with the wind environment and the pollutant diffusion in urban areas. Currently, Steady solutions with RANS models (Steady RANS) are commonly used for this type of studies. However, CFD simulations with Steady RANS have some drawbacks that the reattachment length and pollutant gas concentration are overestimated behind the building, because they cannot reproduce periodic vortex shedding in the weak wind region behind the buildings. Therefore, applying the Steady RANS may be unsatisfactory for predicting pollutant diffusion and ventilation in the weak wind region behind the buildings. In this paper, we aim to provide adaptive experimental data required to verify the accuracy of numerical simulation. In order to show the reliability of experimental data, we evaluated the uncertainty of measurements for wind velocity and concentration, and verified the method for management of accuracy.