Study Of Characteristic Of Natural Wind And The Natural Ventilation Performance

With the generation of the energy crisis and the sustainable development strategy,the international community pay more and more attention to energy issues.While building energy consumption accounts for a considerable large proportion of energy consumption,building energy-saving technologies have received increasing attention.Making full use of the natural ventilation of buildings is an effective way to reduce building energy consumption and improve indoor air quality.At present,the research on building ventilation is mostly on the basis of steady boundary conditions,while the natural wind is not stable,but fluctuates with time in certain rules.In recent years,some studies have showed that in the study of the natural ventilation characteristics of buildings,the conclusion that the fluctuating wind was simplified to the average flow will have some deviation from the actual results.In order to more efficiently study the characteristics of natural wind for better utilize natural ventilation,this paper summarizes the work of researchers at domestic and abroad on the characteristics of natural wind fluctuation,including relevant theories of wind characteristics,prediction methods and simulation models of fluctuating wind,and the application of fluctuating wind theory in natural ventilation.The research focuses on fluctuating wind velocity,turbulence intensity,correlation function,turbulence integral scale,and fluctuating wind power spectrum.Secondly,in this paper,several simulation methods of natural wind are summarized.The harmonic superposition method and time series method are used to simulate and verify the wind velocity,according to the MATLAB programming.Besides,the wind velocity of natural wind in the Xi’an area was measured by a three-dimensional ultrasonic anemometer,and the wind velocity at the 10-meter high wind field was obtained.The SPSS was used to process the measured wind velocity.The ARIMA method was used to model the wind velocity,and the feasibility of the ARIMA method was analyzed.The aim is to help the study of building natural ventilation closer to reality.Finally,the software Fluent is applied to simulate the natural wind under the fluctuating wind flow field,and the ARIMA method was programmed to generate a random fluctuating wind velocity time course as the entrance boundary condition of the large eddy simulation.At the same time,the steady-state natural ventilation is numerically simulated,and the simulated and calculated ventilation volume is analyzed and compared to verify the rationality and scientificity of the wind velocity model,and the difference between the steady state and unsteady state natural ventilation effects is verified.The research results of this paper provide theoretical basis and basic methods for the effective use of wind pressure natural wind in practical projects,so as to promote better development of building design towards energy saving and comfort.