Study On The Refractive Index Power Spectral Function Of Atmospheric Turbulence Under Different Acoustic Disturbances

Atmospheric turbulence is a widespread and irregular natural phenomenon caused by solar radiation,wind shear and thermal convection.It is an inevitable channel influence factor in the process of optical information transmission of ground to air links.As a carrier of information and energy,sound waves are accompanied by energy transfer during the propagation process,which has an impact on the spatiotemporal distribution and evolutionary structure of atmospheric turbulence.This article main work includes:1.Firstly,atmospheric turbulence is composed of many vortices with different refractive index and scale,the concept and basic calculation formula of inner and outer scale of turbulence are introduced Secondly,based on the wave equation and turbulent energy balance equation,the propagation model of sound wave energy in atmospheric turbulence is established,and the expression of the energy distribution of sound field excited by sound wave is derived,at the same time,different coordinates system were established,the energy distribution of the sound field excited by the plane,cylindrical and spherical sound waves in a certain range of space,and finally,due to the introduction of the energy of the sound field,the energy of the turbulence itself is affected,therefore,by changing the geometry of the sound source,the power of the sound source and the frequency of the sound source,to explore the change rule of turbulent space-time structure under acoustic wave disturbance.2.According to different atmospheric turbulence conditions,the distribution of several typical Kolmogorov refractive index power spectral functions without acoustic disturbance is simulated,considering the effect of acoustic wave propagation on the scales of turbulence,the three-dimensional distribution of the refractive index power spectral function of atmospheric turbulence with spatial wavenumber and acoustic wave propagation distance is simulated,a diagram of Kolmogorov refractive index power spectrum varying with source power is drawn.3.According to the atmospheric turbulence stratification model,there is a significant inconsistency between the Kolmogorov theoretical model and the observed experimental data.In order to more accurately describe the properties of turbulence,an anisotropic Non Kolmogorov refractive index power spectrum model was established,and the distribution of isotropic Non Kolmogorov refractive index power spectrum with power law and anisotropic Non Kolmogorov refractive index power spectrum with anisotropic factors under silent wave disturbance was numerically simulated;The conclusion of integrating the effects of sound wave transmission on the internal and external scales of atmospheric turbulence was studied,and the effects of different sound wave transmissions on the isotropic and anisotropic Non Kolmogorov refractive index power spectral functions were studied.The results show that the inner and outer scales of atmospheric turbulence change with the propagation distance of plane sound wave,cylindrical sound wave and spherical sound wave,in particular,the farther the cylindrical and spherical sound waves travel,the closer the inner and outer scales of the turbulence are to the initial scales when the acoustic wave is not disturbed,at the same time,when other source parameters are fixed,the larger the source power is,the stronger the disturbance to turbulence is,and the larger the effect on turbulence scale is,the effect on the turbulence scale is not particularly obvious.Considering the influence of sound wave transmission on the scales of turbulence,it will have an impact on the magnitude and distribution of the atmospheric turbulence refractive index power spectrum function.Since the Tatarskii spectrum and Hill spectrum models only include the influence of the turbulent internal scale,the impact of sound wave transmission on the refractive index power spectrum mainly manifests in the dissipative region.In the Von Karman spectrum and modified Hill spectrum models,both the turbulent internal scale and the turbulent external scale are included,So the influence area of sound wave transmission on the refractive index power spectrum includes not only the dissipation zone,but also the inertia zone.The larger the sound source power,the greater the energy of the transmitted sound wave,and the stronger the impact on turbulence,thus having a greater impact on the refractive index power spectrum.In the same way,the transmission of sound wave will affect the power spectrum functions of isotropic and anisotropic Non-Kolmogorov refractive index,the power spectrum level of isotropic Non-Kolmogorov refractive index decreases gradually,and the anisotropy coefficient changes when the spatial wavenumber is consistent with other sound source parameters,the power spectrum order of anisotropic Non-Kolmogorov refractive index increases with the decrease of anisotropy factor.