Development of an Alternative to the E9 Procedure for Predicting Boundary-Layer Transition

摘要

A method has been devised which can be used in conjunction with linear-stability theory for predicting boundary-layer transition. As with the classical 'eq' procedure, for a given frequency the growth of a disturbance is computed downstream of the initial point of instability using the linearized equations of motion. In contrast to the 'eq' procedure in which the linearized equations are used all the way to the inferred transition point, an approximate set of long-time averaged equations which account for nonlinearity is used to describe the ultimate nonlinear growth of the disturbance. Because the new method accounts for nonlinear processes it holds promise as a more physically sound procedure than the eq method for determining the point at which a boundary layer undergoes transition to turbulence. (Author)