Analysis of Flow Field around Rectangular Prism under Forced Vibration Based on the Application of DMD

抄録

In the turbulent flow field around the rectangular prism, the span-wise correlation of surface pressure and buffeting force near the leading edge is higher than that of the approaching flow. It was found that this phenomenon is affected by vortex shedding or two-dimensional flow structure of the separation bubble. In this research, to study the specific mechanism, the authors visualize and capture the flow structure around a rectangular prism with chord/depth ratio of 8.0 under forced vibration in turbulent flow and smooth flow by PIV (Particle Image Velocimetry) analysis. Then, the flow velocity fields are decomposed by DMD (Dynamic Mode Decomposition) to discuss the flow structure and mechanism of increase of spatial correlation along the span-wise direction in the vortex shedding region. The results are compared with the static case, which implies that vibration changes the flow field considerably and the former proposed flow structure is applicable to both static and vibration cases.