A Comparative Study On The Sound Characteristics Of Aerodynamic Vortex Whistles At Different Inlets

With the development of society,power ultrasound technology has become more and more widely used,and it is becoming more and more popular in national defense and national economy.The vortex whistle structure is simple,easy to manufacture,easy to use,and the fluid source is easily available.Acoustic radiation characteristics are important criteria for judging the advantages and disadvantages of ultrasonic sounders.The reason for restricting the application of vortex whistle is that its acoustic radiation efficiency is low.The key to this situation is the lack of research on the mechanism of whistling whistle.Based on this,in view of the defects of the traditional vortex whistle,this paper proposes a double inlet vortex whistle and compares the two.This paper first introduces the research situation and significance of vortex whistle,then introduces the basic theory of computational fluid dynamics and aeroacoustics.From the theory,it analyzes the theory suitable for studying vortex whistle,and provides theoretical basis for the later simulation calculation.For two different inlet tube vortex whistle,first establish a physical model and then determine the grid of the vortex whistle.In the first part,the same simulation analysis method is used to compare the flow field inside and outside the vortex whistle of the single inlet tube and the double inlet tube.The distribution of velocity,static pressure and turbulent kinetic energy of the two vortex whistle is obtained,and the main vortex whistle is analyzed.Sound source sounding area.The second part mainly analyzes the sound field inside and outside the vortex whistle,and compares the laws of the two vortex whistle radiated sound power and radiated sound frequency under different inlet pressures.The relationship between the flow field and the sound field of the two vortex whistle is summarized.Studies have shown that the vortex whistle mainly generates sound waves when the airflow enters the cavity from the inlet pipe and flows out from the outlet pipe,and both of the turbulent energy and the sound power level appear to have maximum values.The static pressure,velocity,turbulent kinetic energy of the flow fields inside and outside the two vortex whistle are symmetrically distributed along the axis of the cavity,and the symmetry of the double inlet tube vortex whistle is significantly better than that of the single inlet tube.By comparing the flow field characteristics and sound source characteristics of the two vortex whistle,it is concluded that the two dipole horns radiate sound waves mainly dominate the dipole sound source under the same inlet pressure,and mainly focus on the fundamental frequency,double inlet The radiated sound power of the whirlpool is 10 times larger than that of the single inlet.The radiated sound frequencies of the two vortex whistle generally increase with the increase of the inlet pressure,double inlet vortex whistle radiated sound frequency is closer to ultrasonic frequency.Through the above research methods and conclusions,the vocalization mechanism of the whirlpool is obtained.Under the same inlet pressure,the double inlet tube vortex whistle sound radiation frequency and sound radiation efficiency are higher than the single inlet,which has certain guiding significance for the use and improvement of the vortex whistle.