Transport theory for acoustic waves with reflection and transmission at interfaces

Transport theoretic boundary conditions are derived for acoustic wave refle ction and transmission at a rough interface with small random fluctuations. The Wigner distribution is used to go from waves to energy transport in th e high frequency limit, and the Born expansion is used to calculate the eff ect of the random rough surface. The smoothing method is also used to remov e the grazing angle singularity due to the Born approximation. The results are presented in a form that is convenient both for theoretical analysis an d for numerical computations. (C) 1999 Elsevier Science B.V. All rights res erved.