M. F. Werby
NRL, Theor. Acoust. Codes 223 and 221, Stennis Space Center, MS 39529
A new normal mode method capable of predictions to very high frequencies is developed. The objective is to compare predictions of ray theory with the more exact normal mode theory to determine how well and at what point ray theory agrees with normal mode theory. The approach is to compare transmission loss curves computed by both methods. Discussion of the discrepancies are made and comments will be made on how improvements can be implemented. In strong ducting problems it is shown that there is a strong association between the lower order modes and the ray trace results.