Transition Prediction and Control for Airplane Applications

Transition prediction and laminar-flow control are considered from an airplane-indu stry perspective. A hierarchy of transition-pr ediction methods, intended for different applications, is discussed. Nonlinear amplitude-based methods offer the greatest potential for prediction over the full range of practical flow conditions. However, these methods are the most demanding in terms of their computational effort and in terms of their requirements for initial conditions. We consider two additional approaches intended for moderate- to low-turbulenc e environments. The first approach is a linear amplitude-based method which combines receptivity, linear growth, and an amplitude correlation for predicting transition. The second approach is a variable .AT-factor method - derived as a limiting case of the linear amplitude method. The discussion of laminar-flow control focuses on an industry assessment of viability; some of the critical issues for application are considered.