In this paper, a transfer matrix method (TMM) for solving the frequency domain response of the straight pipe conveying fluid is established based on 14-equation model by Laplace transformation. The reliability of the method is verified by the frequency domain response results of fluid velocity and structural axial stress in the pipe under free boundary conditions. Then, based on the transfer matrix method, the influence of boundary conditions and fluid density on the frequency domain response characteristics of pipeline vibration is analyzed. The numerical results show that the boundary conditions have a significant effect on the amplitude of the vibration response of the pipeline, but the amplitude changes little under the fixed and simply supported boundary conditions. The vibration frequency is inversely proportional to the density, while the axial vibration response amplitude increases with the increase of fluid density, and the change of density has little effect on the transverse vibration response.
An experimental investigation was conducted in a high speed wind tunnel to explore the effects of mass-injection on cavity flow characteristics. Detailed static-pressure and fluctuating pressure measurements were obtained at the cavity floor to enable the effects of the mass-injection at the leading edge to be determined. Results indicate that varying mass-injection hole number and the flux rate of mass-injection has no significant effect on cavity flow characteristics. However, mass-injection can reduce the cavity static pressure gradient when the cavity flow type is transitional-cavity flow. The study also indicates that Mach number can influence the effect of mass-injection on cavity fluctuating pressure distributions, and at supersonic speeds, mass-injection can suppress the cavity tones effectively.
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