PIV Experimental Research And Numerical Simulation Of The Flow Across A Building

There are two parts in the dissertation: One is the experimental research on the flow across a building with particle image velocimetry (PIV) and the high procession pressure sensor. The other is numerical investigation by using universal CFD software, which is the comparison and supplement to the result of the experiment.How to simulate the atmospheric boundary layer (ABS) in the wind tunnel is introduced, which is known as the precondition of this experiment. Then, considering some conditions of comparability, a required profile of simulated ABS in wind tunnel was tested with PIV.The experiment was done in the simulated ABS. According to the wind direction, there are two testing conditions: 0 degree and 180 degree. As to the coming flow, steady flow and unsteady flow are considered here. When the coming flow is steady, through further data processing, time-averaged and instantaneous parameters can be achieved. The cortex structure and the pressure distribution on the surface are clearly shown in the mean flow results. And instantaneous results display not only the pseudo-periodic vortex evolvement, but also positions of the maximum fluctuation values of the pressure coefficient Cpi.When the coming flow is unsteady, it is concluded that the dividing line of the press and suction on the surface of the building is moving fore and aft as the velocity is varied periodically. And comparison is done between the steady coming flow and unsteady coming flow in special section, which indicates the relationship of velocity between thesteady coming flow and unsteady coming flow.Instead of using the traditional way, k-ε turbulence model together with the damping near-wall function, a new model (V2F) is introduced. The results of the numerical simulation are compared with the experimental results. It is validated that the V2F model is more suitable to the problem on discuss, and the results is more approach to the experimental results.