A Viscous—Inviscid Interaction Method for Computing Unsteady Transonic Separation

Unsteady aerodynamics: retrospect and prospect

“…43 -44 ' (Fig. 23) and on supercritical aerofoils* 45 ' above the design lift coefficient. Although the precise mechanism of this shock oscillation is still the subject of research, there is evidence that the oscillations depend primarily on three factors.…”

“…The original method, due to Levy* 44 ', uses the thin-layer Navier-Stokes solution. Another method, due to Le Balleur* 45 ', uses an inviscid, transonic small perturbation method in conjunction with a quasi-steady boundary layer method which includes separation. This method appears attractive for predicting whether a given aerofoil design will have a periodic shock oscillation at transonic speeds, and over what range of Mach number and lift coefficient the instability would occur.…”

Computation of steady and unsteady control surface loads in transonic flow

“…This approach has been used to study unsteady flows in two dimensions using various inviscid formulations (e.g., see Refs. [7][8][9]. However, applications to unsteady three-dimensional flows are comparatively limited; 10 the author is not aware of any previous applications to the analysis of three-dimensional wings with control surfaces.…”

An interacting boundary layer method for unsteady compressible flows

“…The quasi-simultaneous method appears to work better for these cases and has been implemented successfully using the low frequency LTRAN2-NLR TSD code and the quasi-steady integral boundary layer equations. Le Balleur and Girodroux-Lavigne have developed a time accurate method based on the unsteady compressible boundary layer continuity and momentum equations using a momentum defect integral approach, based on the analytical boundary layer method and shape function of Le Balleur, and the high frequency small disturbance equation[81]. The boundary layer equations are time accurate, at least for flows not requiring the unsteady energy equation.…”

“…Le Balleur[81] presents results for several oscillating airfoils and for an airfoil with an oscillating spoiler. Several of these have shock induced separation extending from about mid chord to the trailing edge.…”