Numerical Simulation Study On Typical Atmospheric Boundary Layer Flow Based On Similarity Theory

With the continuous development and improvement of CFD technology, the numerical simulation technology of urban micro climate is used in scientific research and engineering application by more and more people. Research area of urban micro climate from the small block scale to the large scale of the city, need more and more grid, which requires more advanced computer hardware equipment. This limits the application of this technology in the computer with ordinary configuration. Therefore, it is expected that scale model derived from the similarity theory instead of the prototype was simulated, to reduce the number of grid computing, and the results of the simulation results can restore to a prototype. At present, the domestic and foreign scholars research little in this area.In this paper, which based on the similarity theory, the numerical simulation method based on Fluent software and SST k-w model is used to verify the feasibility of similar simulation of wind environment in residential district based on the background of neutral atmospheric flow, and to verify the feasibility of similar simulation of the heat environment of residence district based on the consideration of convection and conduction heat transfer. According to the similarity theory, this paper deduces the corresponding similarity criteria of the above two kinds of conditions. Taking the residential district as the prototype, according to the similarity criterion of equal scale and full-scale model scale model of ideal medium physical properties and boundary conditions were designed. The conclusion is that:(1) Based on the background of the neutral atmospheric flow:a) the scale model derived from the similarity theory of the dimensionless of simulation results and full-scale model of dimensionless simulation results are basically consistent, indicating that the ideas use the scale model derived from the similarity theory of the simulation results to restore in a prototype is feasible, and achieve the expected objective that the number of grid scale model less than the full scale model; b) the region exist large errors between Scale model and full-scale model of dimensionless results mainly between the front and behind the construction of the building; c) the scale model and full-scale model with the best agreement on the road; d) wind speed relative wind pressure coefficient is more prone to large errors; e) the relative error of the wind pressure coefficient is not more than 20%.(2) In considering the convective heat transfer and heat conduction conditions:a) the scale model derived from the similarity theory of the dimensionless of simulation results and full-scale model of dimensionless simulation results are basically consistent, indicating that the ideas use the scale model derived from the similarity theory of the simulation results to restore in a prototype is feasible, and achieve the expected objective that the number of grid scale model less than the full scale model; b) scale model and full-scale model of dimensionless results exist large errors in the region mainly in the building on the leeward side of and building on the left side of the district; c) large temperature relative error has a great influence on wind speed and a wide range of wind speed; d) the relative error of the wind pressure coefficient is not more than 20%.