Papers by Author: He Feng Dong

Abstract: A mathematical model is presented to describe the scattering of a fast compressional plane wave (fast P-wave) incident at an arbitrary angle on isotropic cylinder embedded in a fluid-saturated porous medium. The expressions of components of solid and filtration displacement, pore fluid pressure and stress tensor in porous medium are obtained by potential function using the Biot’s theory and that of isotropic cylinder are also given. We investigate the properties of the form function of a backscatted fast P-wave for cement and steel cylinder system. It shows the influence of incident angle on form function for steel is more obvious than that for cement cylinder and form function curves are very different between steel and cement cylinder.

Abstract: Acoustic wave propagation in fluid-saturated porous cylindrical shell is investigated in this paper by using the Biot’s theory. The Expressions for acoustic pressure and radical displacement in and out fluid, the expressions for components of solid and filtration displacement and pore fluid pressure and stress tensor are given. The numerical simulation is operated on acoustic field in fluid of poroelastic cylindrical shell, and the full-waveform is obtained by Fourier transform, and acoustic pressure field in frequency-wavenumber domain is analyzed, as well as the influence of inner and outer radii on wave amplitude is discussed. It shows that if the thickness of shell remains constant, the amplitude of longitudinal mode increases and that of Stoneley wave decreases when inner and outer radii increasing. In the fast formation the influence of inner and outer radii on the amplitude of longitudinal mode is notable. In the slow formation the amplitude of Stoneley wave will decrease with inner and outer radii increasing.