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On the inner structure of streamwise Görtler rolls

1988; Elsevier BV; Volume: 9; Issue: 1 Linguagem: Inglês

10.1016/0142-727x(88)90025-2

1879-2278

Hassan Peerhossaini, José Eduardo Wesfreid,

Fluid Dynamics and Vibration Analysis

Counterrotating streamwise rolls are generated on a concave wall due to Görtler instability mechanism and are studied as they emerge into a stragiht after-section where the destabilizing mechanism is relaxed. Once the Görtler rolls develop, increasing the Görtler number causes the center of the rolls to move off the wall. At higher Görtler numbers, a higher mode of instability sets in, which appears as side oscillations of the interface plane between two neighboring rolls. Amplified oscillations bend the rolls drastically so that their centers move close to the wall. A higher mode of instability can be obtained at higher Görtler numbers. This mode is characterized by lateral wandering of the rolls. Eventually when the boundary layer becomes turbulent, the distorted rolls keep their intermittent presence.