The thermal behaviour of a sample submitted to a sinusoidal optical irradiation or a sinusoidal electronic irradiation is modelled in axisymmetrical two- dimensional geometry. This modelling mixes an integral transform and a one-dimensional thermal harmonic response. It shows the spherical thermal behaviour of the harmonic heat diffusion. The same solving method is applied to the Navier-Stokes equation using one-dimensional acoustic harmonic responses. The latter solution leads to the calculation of the displacement field. Finally, the two heat sources are compared from thermal and thermoelastic points of view.