Development of an Aerodynamic and Aeroelastic Prediction Capability for Cascades in Unsteady Transonic Flow

摘要

A high-frequency version of the Ballhaus-Goorjian code LTRAN2 has been adapted to represent unsteady aerodynamic phenomena in transonic cascade flow. The modifications to the algorithm for high frequencies differ from those of Rizzetta and Chin in two ways: first, a second-order difference for the jilsi (xt) term instead of a first order one is used, and second, a wake condition derived for the transonic small disturbance equation is applied. Then, in order to represent the cascade geometry, periodic boundary conditions and periodic tridiagonal solvers must be introduced. Examples of both oscillatory flows and indicial responses are presented. Application of the indicial method to unsteady cascased is discussed. Future work on the code will extend the applicability of the code to staggered, highly cambered cascades. (Author)