Abstract:
In response to the prominent issue of aircraft noise in windy and sandy environments, a numerical method has been applied to combine the Euler-Lagrange approach with the FW-H integral equation for the simulation of the mixed aerodynamic noise of solid particles, and the multiphase flow field and aerodynamic noise characteristics of the flow around a cylinder under windy and sandy conditions are studied. The aerodynamic force characteristics, flow dynamics, and noise characteristics of the single-phase and gas-solid two-phase flow around a cylinder are analyzed through a comparative study integrating theory of vortex dynamics. The mechanisms of interaction among particles, the vortex and noise are investigated, and the physical mechanisms of the flow and noise generation in the gas-solid flow around a cylinder are elucidated. The results indicate that, under the same inflow conditions, the time-averaged drag coefficient and surface pressure fluctuations on the cylinder of the gas-solid two-phase flow significantly increase compared to the single-phase flow field. A high-concentration area with a bow-shaped distribution of particles is observed on the upstream side of the cylinder, where small vortex structures appear. Moreover, the surface pressure fluctuations of the gas-solid two-phase flow increase, and the interaction area between the strong vorticity and the strong strain, represented by the Lamb vector divergence which is also the noise source term, increases. These two factors contribute to an increase in the flow field noise.