Research On The Cylindrical Bubble Dynamics In The Viscoelastic Fluid

Bubble dynamics studies the growth,collapse and oscillation of bubbles in liquid.Bubble dynamics behavior widely exists in real life,including common natural phenomena such as animal predation,high-speed rotation of ship propeller,stable operation of hydraulic turbine,heat transfer of water wall in thermal power plant,biomedicine and other important processes of national production and construction,and the existence of bubbles can have a key impact on the results.Therefore,the study of bubble dynamics is very urgent and necessary.In this paper,the dynamic behavior of cylindrical bubble in incompressible viscoelastic fluid is considered.Based on Kelvin Voith linear model,the motion equation of cylindrical bubble is derived,and the small perturbation method is used to solve and analyze the equation.This paper focuses on the motion and oscillation of a cylindrical bubble in the presence of a small external acoustic field.Because the perturbation method has the advantage of solving the simple harmonic vibration differential equation under small disturbance,the linear oscillation solution and harmonic oscillation solution of the motion equation of cylindrical bubble in viscoelastic fluid are obtained by using the perturbation method.Through the numerical analysis of the linear and harmonic oscillatory solutions,the important factors affecting the results of the linear and harmonic oscillatory solutions are discussed quantitatively,and the physical mechanism is analyzed deeply.It is found that the existence of liquid elasticity increases the natural frequency and damping of bubble oscillation.For the linear oscillation solution of the bubble oscillation equation,with the increase of bubble size,the amplitude of the linear oscillation solution first increases and then decreases,and there will be a sharp change.The sharp change is due to the "resonance" caused by the close relationship between the sound field frequency and the natural frequency of the bubble oscillation;The higher the frequency of the sound field and the smaller the elasticity of the liquid,the smaller the equilibrium radius corresponding to the resonance of the bubble;The influence of liquid elasticity on the linear oscillation solution decreases with the increase of elasticity.For the bubble oscillation equation,the change of harmonic oscillation solution is more complex than that of linear oscillation solution.The obvious difference is that the amplitude of harmonic oscillation solution changes sharply twice during the bubble growth process.The first dramatic change is caused by the natural frequency value being close to twice of the sound field frequency value,The second drastic change is due to the fact that the value of natural frequency is close to the value of sound field frequency;The influence of the frequency of sound field and liquid elasticity on the harmonic oscillation solution of bubble oscillation equation is similar to that on the linear oscillation solution.