In a three-dimensional boundary-layer flow, stationary so-called crossflow vortices appear, which can be described successfully by a linear stability theory. However, the transition of the laminar flow to a turbulent flow is governed by nonlinear interactions between stationary vortex structures and instationary disturbances. In order to incorporate such interactions into a transition model, the classical primary stability theory is extended by a theory of secondary instability. Here a new basic flow, which is composed of the three-dimensional boundary-layer flow plus a primary disturbance corresponding to the stationary crossflow vortices, is investigated locally for instability. Results of a secondary stability analysis for the flow over the swept DFVLR-F5 model wing show the importance of certain disturbances within the boundary layer, which are waves travelling preferably oblique to the potential flow direction.
Theoretical investigation of secondary instability of three-dimensional boundary-layer flows
Theoretische Untersuchung sekundaerer Instabilitaet von dreidimensionalen Grenzschichtstroemungen
AIAA-Papers ; Jun ; 1-11
1987
11 Seiten, 12 Bilder, 25 Quellen
Aufsatz (Konferenz)
Englisch