Research And Verification Of Unsteady Wind Characteristics In Low Speed Wind Tunnel

In recent years,the domestic and foreign rela ted research institutions in the construction of the structure of the atm ospheric boundary layer of the resonance caused by the phenomenon of structural dam age increasingly concerned.To study this phenomenon,we need to design a wind tunnel that can sim ulate the natural wind speed.The wind s peed of wind tunnel test section should not only realize the simulation of steady-state wind speed,but also change the wind sp eed to meet certain experimental requirements,that is,gust spectrum can be realized in low-speed wind tunnel.The purpose of this paper is to analyze the in fluencing factors of fluid velocity in the wind tunnel,and to change the input power of the m otor to achieve the required gust simulation,and to verify it in the actual wind tunnel.The structure and operation principle of the wind tunnel are analyzed and simplified into a one-dimensional model.The air and power system are analyzed and the co rresponding control equations are listed acco rding to th e principle of fluid m echanics.The mathematical model of the solution is obtained by the analysis of the equations.MacC ormack two-step difference method is used for the fluid part,and the fourth-order Runge-Kutta method is used for the motor fan model.The mathematical model is implemented by Matlab software,and th e input power is obtained as a function of the wind speed in the test section.In this pape r,after the wind speed is st abilized,the wind speed curve is obtain ed by inputting sinusoidal voltage.The simulation results show that the wind velo city is also sinusoidal in the test section,and its frequency is consistent with the frequency of the input voltage through fast Fourier analysis.In the actual wind tunnel te st data obtained by the harmonic analysis is also consistent with th e simulation results,it can be through the above method to change the motor input power to achieve gust spectrum simulation.