Investigation of Spatial Coherences of Aerodynamic Loads on a Streamlined Bridge Deck in an Actively-Controlled Wind Tunnel

Abstract

Two-dimensional flow fields were simulated in an actively-controlled wind tunnel by using multiple fans and active-vibration grids. On coming flow features and aerodynamic loads on a streamlined bridge deck section model were measured simultaneously. Experimental result shows that the spatial coherences of on coming flows and aerodynamic loads are both influenced by on coming flow features. Longitudinal and vertical flow features have different effects on spatial coherence of aerodynamic loads. The shape of the spatial coherence function versus frequency curve does not always satisfy an exponential law, but sometimes shows an inverse form in the low-frequency region. A new empirical model is proposed and compared with the traditional exponential one. This new model shows good performance in reflecting spatial coherences of both oncoming flows and aerodynamic forces under different flow conditions.