Thermal waves scattering by two subsurface spherical cavities and temperature distribution

The hole defect is one kind of the most common defects for engineering materials. The non-contacting photothermal nondestructive testing is widely used to ensure the safety and reliability of the materials. Based on non-Fourier heat conduction law and employing the methods of wave function expansion, the thermal waves scattering and temperature distribution at the surface of semi-infinite metal material with double subsurface spherical holes were investigated in the paper. The analytical solution and the numerical calculation result of the problem were presented. The effects of geometrical parameters of the defects and the physical parameters on surface temperature distribution of the semi-infinite material were analyzed. The computed results show that the relative thermal diffusion length, the incident wave number and the buried depth have great influences on the surface temperature and the maximum surface temperature. And the thermal wave scattering between the two holes can be ignored when the hole pitch is big enough.