Numerical Simulation of Flow Loads on Large Cantilevered Roofs of Gymnasium
|Keywords||long-span overhung structure computational wind-engineeringnumerical simulated turbulence model wind characteristics|
Large-span cantilever structure has been widely used in the construction sector because of its beautiful architecture and unique function of coverage.However the structure belongs to the typical wind-sensitive structures. The wind load design problem has become the difficulty of structure designing and the focus of structural wind engineering research.At present the study on this problem is not mature, still in its infancy. From the practical engineering applications,in most cases the wind load design parameters is determined by wind tunnel simulation test, and the current load code for the design of building are not powerful design basis.The flow of the wind around the buildings belongs a complex flow of blunt body. The airflow field is a very complex turbulent field which consists of some complicated movements,like separation, reflux vortex,etc. At present, it’s difficult to solve the problem with theoretical method. Field measurement and wind tunnel test research have many advantages,like the results are comparatively accurate.However, they need to spend a lot of time, human, material and their applicability is not strong.Also they has not been widely used in the practical engineering applications yet. To find out new ways has become the wind engineering research needs. Along with the development and improvement of the turbulence model and computer technology, computer simulation technique has become more and more mature, and using numerical simulation method to solve this problem gradually becomes a powerful means of wind engineering research. This paper is about that using the method to simulatively research the wind load of the gym’s large cantilevered roof structure to get the function response of the wind to this kind of building structure and provide references for this kind of structure design and further study.First, this paper reviews the process of the large cantilevered roof structure wind engineering research, and describes the wind’s characteristics and it’s flow characteristics, and then expounds the structural wind engineering’s numerical simulation theory and its calculation method, and through analysis and derivation gets the control equations and discrete equations under the three-dimensional steady-state second-order upwind scheme. Second, respectively study the problems that will turn up on numerical simulation process and gives suggestions to how to choose and apply them. These problems include the establishment of geometric model, confirming calculating watershed, meshing, selecting boundary condition type, ascertaining the reference pressure location, choosing suitable turbulent model, setting parameters, etc. And they are put into practical engineering.Third, use the computational fluid dynamics software (FLUENT) and FLUENT open-platform UDF function to compile the procedure of atmospheric boundary layer wind gradients, and to simulate the win load situation of the gym’s large cantilevered roof structure; next respectively compare and analyse structure wind load under different angles and ground roughness; then get the relevant conclusion. Four, by using the finite element software (MIDAS) to analyse the bearing capacity of roof structure, get the structure internal force under variety of working conditions; then compare and analyse those data to get conclusion.