The Experimental And Numerical Studies Of Hartmann Whistle Sound Field Characteristics

In this paper,based on the acoustic analogy method of FW-H equation,the radiation field distribution of Hartmann whistle is studied.The Hartmann whistle is a relatively mature high-intensity sound source and is widely used in aviation,petroleum,and sonic cleaning.The sound performance is mainly divided into two aspects.On the one hand,the vocalization intensity has been studied.The previous studies have been fully studied and the relevant experience has been obtained.On the other hand,it is the sound directionality which is also the focus of this study and the related improvements is proposed for practical applications.In this paper,the finite element analysis software Fluent is used to solve the FW-H equation.The influences of the relationship between the nozzle distance from the resonator,the cavity length,the pressure,and the relationship between the position of the nozzle and the resonator are analyzed.Two different nozzle diameters of 5mm(small size)and 6cm(large size)were used to carry out experimental and numerical investigations on the small-sized Hartmann whistle.The experimental results were compared with the numerical calculation results to verify the accuracy of the numerical calculation method..For the large-size Hartmann whistle acoustic field characteristics,the influence of the position relationship between the nozzle and the resonator on the distribution of the sound field is proposed and numerical calculations are performed.The sound field distribution in the direction of the vertical cavity is studied,and the conclusion of the small size Hartmann whistle is compared with the conclusion of the large size Hartmann whistle.Through calculations and experiments,the distance R between the nozzle and the resonator has no influence on the fundamental frequency and the acoustic directionality of the Hartmann whistle,but it has an influence on the sound pressure level.The length L of the resonator has no effect on the sound pressure level and directivity of the Hartmann whistle,but it has an effect on the sound frequency.As L increases,the voicing frequency moves toward the low frequency.The pressure P has no effect on the sound frequency,but it has an effect on the acoustic directionality and sound pressure level.The relationship between the position of the nozzle and the resonator h has little effect on the fundamental frequency of the utterance of the Hartmann whistle.However,it has an effect on sound pressure level and sound directivity.