Wind pressure characteristics of large-span terminal roof under mesoscale typhoon

Roof partial damage is the most typical form of wind-induced damage of long-span terminals, especially, in China southeast coastal areas where strong typhoons frequently occur. Here, aiming at the problem of excessive simple typhoon model in the existing civil engineering theory system, the weather forecast model WRF based on the non-static equilibrium Euler equation model was introduced to simulate the typhoon Catfish with higher space-time resolution. Xiamen international airport terminal was taken as an example. Firstly, the triple nested mesoscale WRF technique was used to analyze the typhoon Catfish near-ground 3-D wind field characteristics, and the boundary layer wind speed profile was obtained based on nonlinear least squares fitting. Then, the user-defined function was used to determine the inflow wind field of small scale CFD numerical simulation, the standard k-ε turbulence model was used to simulate the typhoon wind field and wind field distribution of large-span terminal structure in good state class A wind field environment, respectively. The most unfavorable incoming flow's wind direction angle was determined based on the pressure difference analysis between upper and lower ends of suspended eaves. Finally, the extreme value wind pressure characteristics of the terminal roof under the most unfavorable working conditions were deeply explored based on the large eddy simulation technique, and the flow field and wind pressure forming mechanisms of the roof under typhoon and class A wind field were presented contrastively. The results showed that WRF model can be used to effectively simulate the near-ground typhoon wind field, and the fitted typhoon profile index is 0.091; considering effects of mesoscale typhoon can increase the roof's average wind pressure and extreme value one, the latter can be increased up to 31%; the study results can provide a scientific basis for typhoon load choosing and anti-typhoon design of such long-span terminal roofs. © 2019, Editorial Office of Journal of Vibration and Shock. All right reserved.