Large Eddy Simulation Of Wind Load And Fluid Structure Interaction Analysis Of High-rise Building With Improved Sub-grid Scale Model

Due to the high flexibility, light weight and small damping, wind load plays the main role in design for the tall building structures. So it is very important to accurately predict the wind pressure on the building surface and further study the wind-induced response of tall buildings. With the rapid development of Computational Fluid Dynamics(CFD) technique, Large Eddy Simulation(LES) has become a major research tool in computational wind engineering. An inflow turbulence generation method called Discretizing and Synthesizing of Random Flow Generation(DSRFG) and an improved dynamic one-equation model for LES were adopted to conduct the numerical simulation of wind loading on tall buildings. The simulated results were compared to TPU wind tunel test results with good accuracy. Meanwhile by ultilizing the simulated inflow fluctuating wind velocity by DSRFG and sequence fluid structure interaction method, the wind load characteristics and wind-induced response were analyzed for CAARC building. The main research contents and conclusion are as follows:(1) The inflow and selection of the sub-grid scale model were major steps in LES procedure. Three types of inflow turbulence generation methods were introduced by comparing their advantages and disadvantages, and the principle of three common sub-grid scale models are summarized. The improved sub-grid scale model which combines the advantages of dynamic one-equation model and WALE model was briefly introduced in the thesis.(2) Two types of the Fluid Structure Interaction(FSI) methods for CFD are described: sequential methods and monolithic methods. The principle and implemtent procedure of sequential methods are briefly introduced for the fluid structure interaction analysis. The mechanism and advantages of ALE and three kinds of dynamic mesh updating methods are also introduced in this paper.(3) By applying the DSRFG and the improved sub-grid scale model, the wind loading on an isolated rectangular tall building with 1:1:3 ratio was simulated by LES in Fluent software at zero degree wind direction. The CFD simalted results were compared with those from the TPU wind tunel database for the same building with good accuracy, demonstrating the effectiveness of the proposed large eddy simulation method in this study..(4) Wind loading on the surface of the CAARC rigid model is also conducted by the large eddy simulation method with DSRFG and the improved sub-grid scale model.The mean wind pressure coefficient at 2/3 height of the building, the along-wind force spectra, across-wind force spectra and torsional moment spectra at each building levels are analyzed, for this building. The flow field and the wind load characteristics of the rectangular building show the similar phenomenon to that of the tall building with square section by CFD simuation.(5) By adopting the DSRFG inflow turbulence generation method and sequential FSI method, the wind loading and wind-induced response of CARRC building were conducted in this thesis. The concept of the rigid zone and the Arbitrary Lagrangian Eulerian(ALE) zone were introduced to promot the effectiveness and accuracy of FSI analysis for this building. Comparison results for FSI analysis between the rigid and flexible model shows that the mean wind pressure distributions for these two types are similar. Considering the effect of fluid structure interaction, the mean wind pressure coefficient at front face and the two sides of the building are smaller and changes obviously with time.