Development of a separation vortex for a supersonic flow around a dihedral model for attack angle within the range α = 0 - 24°
A.I. Maksimov, I.N. Kavun
Khristianovich Institute of Theoretical and Applied Mechanics SB RAS, Novosibirsk, Russia
Keywords: dihedral configuration, Mach number, angle of attack, experiment, numerical simulation, vortex system structure, streamlines, pressure drop
Abstract
The emergence and development of a vortex system during the separation of a supersonic air flow on the rib of a dihedral model with face opening angle of 270° was studied in details. The appearance of a separation vortex above the lateral face was detected for a flow with an angle of attack α = 1º. For a case with α ∽ 2º, boundary layer separation occurs near the rib of angle-shaped configuration. With an increase in pressure drop between the top and lateral faces of the model, the separation flow size grows and at an angle α = 3.7º a new vortex form is observed (a secondary vortex). For a flow with an angle of attack α = 8º, a third vortex is clearly observed. This vortex is located above the secondary vortex and it has a minor influence on the pressure distribution and the limiting streamlines behavior on the lateral face. The flow at this angle of attack α results in repeated separations for thin boundary layers near the configuration rib and beneath the enlarged secondary vortex. Within the tested interval of the attack angle α = 8º - 24º , the sizes of those local separations remain almost the same. It was shown that analysis of limiting streamlines patterns and surface pressure distribution cannot fully elucidate the actual structure of complex vertical systems without gaining some additional data.
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