Abnormal refraction of finite amplitude sound wave

Based on Qian's theory, we investigated the reflection and refraction of finite amplitute sound wave on a plane boundary. Under the continuity conditions of the pressure and the normal velocity, some interesting results are obtained. There exists two kinds of refraction waves. One obeys Snell's law; the other quantitatively agrees to the steeply dipping wave observed by Muir et al. A further analysis shows that a double refraction may occur in an extent of the incident angle when ρ 1 /ρ 2 > √C 02 2 /C 01 2 - 1.