PARABOLIZED STABILITY EQUATIONS

Parabolized stability equations (PSE) have opened new avenues to the a nalysis of the streamwise growth of linear and nonlinear disturbances in slowly varying shear flows such as boundary layers, jets, and far w akes. Growth mechanisms include both algebraic transient growth and ex ponential growth through primary and higher instabilities. In contrast to the eigensolutions of traditional linear stability equations, PSE solutions incorporate inhomogeneous initial and boundary conditions as do numerical solutions of the Navier-Stokes equations, but they can b e obtained at modest computational expense. PSE codes have developed i nto a convenient tool to analyze basic mechanisms in boundary-layer fl ows. The most important area of application, however, is the use of th e PSE approach for transition analysis in aerodynamic design. Together with the adjoint linear problem, PSE methods promise improved design capabilities for laminar flow control systems.