| The in-depth contents | |
|---|---|
| Publication year | 2021 |
| Download | |
| Title | Discussion of aerodynamic stiffness and damping of long-span roofs with various shapes based on cfd simulation Part 1: Unsteady aerodynamic forces based on modal wind forces |
| Author | Yuki TAKADATE,Yasushi UEMATSU |
| Summary | The present paper numerically investigates the unsteady aerodynamic forces of the first symmetric and anti-symmetric modes of vibration for three kinds of long-span roofs using a computational fluid dynamics (CFD) with large eddy simulation (LES). The aerodynamic stability of the roofs is discussed based on the characteristics of the unsteady aerodynamic forces, which are represented by the aerodynamic stiffness and damping. Although the building model is two-dimensional (one-way type), the CFD simulation is conducted for three-dimensional domain. The unsteady aerodynamic forces are evaluated based on the wind pressure distributions along the centerline of the roof which is forced to vibrate in the first symmetric and anti-symmetric mode. The vibration amplitude, the vibration frequency and the wind velocity at the mean roof height are varied over a wide range. The aerodynamic forces are investigated on the basis of the unsteady generalized wind forces. The magnitude of unsteady aerodynamic forces changes depending on the vibration amplitude. However, when the unsteady aerodynamic forces are normalized by velocity pressure, tributary area, and normalized amplitude, the normalized values are found to be independent of the vibration amplitude. According to the simulated results, the aerodynamically unstable vibration may occur when the roof vibrates in the anti-symmetric mode. In addition, aerodynamically unstable vibrations may occur on flat and suspended roofs, but may not occur on the cylindrical roof. |