Analysis Of An Acoustic Wave Equation For Media With Cylindrical Symmetry (2.5-D)

The description of 3-D wave propagation in a 2-D medium (2.5-D situation) by means of a simple 2.5-D wave<br>equation enables finite-difference (FD) reference solutions in 3-D with the cost of 2-D modeling. A comparison<br>to alternative approximations in homogeneous and vertical-gradient media shows that the accuracy of a previously<br>suggested approximate 2.5-D wave equation (Liner's equation) depends on how well the rms velocity can be<br>approximated by a constant velocity. Kinematically, Liner's equation works very well up to very high velocity gradients.<br>For an increasing velocity, amplitudes obtained by Liner's equation systematically underestimate true 3-D<br>amplitudes, and for a decreasing velocity, they overestimate the true amplitudes. In conclusion, Liner's equation<br>is a worthwhile alternative to other existing 2.5-D modeling schemes.