DELTAE solves the one-dimensional wave equation, with temperature evolution, in the usual low-amplitude, ``acoustic" approximation. It does not allow superposed steady flow, nor does it include nonlinear effects.
In each pass, DELTAE integrates from BEGINning to HARDEnd or SOFTEnd, with respect to 5 real variables: real T_m, complex p, and complex U. It uses the differential (or simpler) equations appropriate for each segment, with the evolution of these variables in each segment controlled by local parameters, such as geometry and enthalpy flow, and global parameters, such as frequency and mean pressure. Continuity of T_m, p, and U are used at the junctions between segments.
In general, a pass of DELTAE's integration does not arrive at the END with targeted values of all variables. A shooting method is used to adjust chosen initial variables in order to hit the targeted values. The user provides guesses for chosen initial variables.
The table below serves as a guide to choice of guess and target variables:
