NUMERICAL-METHOD FOR PREDICTING TRANSITION IN 3-DIMENSIONAL FLOWS BY SPATIAL AMPLIFICATION THEORY

An efficient second-order-accurate numerical method, based on Keller's box scheme, is used to solve the Orr-Sommerfeld equation for three-dimensional incompressible flows. Transition is computed with the e(n) method and with an eigenvalue formulation based on the saddle-point method of Cebeci and Stewartson. The frequencies needed in transition calculations are obtained from zarfs that correspond to three-dimensional neutral stability curves. The calculation method is evaluated in terms of experimental data on a swept wing and a prolate spheroid at an angle of incidence. In general, the results are in good agreement with measured values.