The invention relates to an implementation method for a mixed absorbing boundary condition applied to a
variable density acoustic wave equation. The implementation method comprises the steps of dividing a whole
simulation region into an internal region and a
boundary region, calculating the
wave field value of a
sound wave of each absorbing boundary layer by using the
variable density acoustic wave equation and a
variable density AWWE (Arbitrary Wide-angle
wave equation) respectively, and performing linear weighting on the two calculation results to obtain the
wave field value of the
sound wave of each absorbing boundary layer. On the basis of realizing a
single variable density AWWE absorbing boundary layer and in 2D (2 dimensional) and 3D (3 dimensional) space coordinate systems, the
wave field value of the
sound wave of each absorbing boundary layer is calculated by respectively adopting a combination mode of
processing edges of the variable density AWWE and
processing angles of a modified 15-degree one-way
wave equation, and a combination mode of
processing faces of the variable density AWWE, the processing edges of the modified 15-degree one-way
wave equation and the processing angles of a 5-degree one-way wave equation, and the mixed absorbing boundary condition of the variable density AWWE is realized. The implementation method can be widely applied to the numerical
simulation of
constant density and variable density
acoustic wave equations.