| Instability of shear flow is one of the main research topics of aeroacoustics. As a typical acoustic source model of shear flow, the self-sustained oscillation of jet-edge system has been widely discussed.The jet-edge system is generally described as an intensive jet out from the nozzle directly rush to the wedge-shaped object with symmetrical geometric. In this paper, flow behaviors of some asymmetric geometrical shaped systems which are controlled by the paralleled or angle shift between the midline of nozzle and wedge-shaped object are discussed based on numerical simulations results.It is found that compared with symmetrical system, the asymmetric system's frequencies of oscillation are almost without any difference when the offset is lower than 20%, but the attenuation of oscillation's amplitude increased quickly with the continued offset as well as a decline of the frequency especially when the offset is higher than 30%. And the value of oscillation's amplitude shows some periodical attribute up and down with linear increase of the angle between the midline of nozzle and wedge-shaped object.This paper insists that all the change of amplitude-frequency characteristic during the oscillation of shear flow which caused due to the asymmetric configuration should be paid more attention in actual conditions. |
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