Instantaneous pressure fields at a corner associated with vortex impingement

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Abstract
The impingement of concentrations of vorticity upon a corner is studied using simultaneous flow visualization and correlation of pressure fluctuations, revealing the relations between the instantaneous pressure fields along the top and front faces of the corner and the instantaneous distortion of the incident vortex. By varying the transverse offset of the corner relative to the incident vortex, several distinct and consistent patterns of incident vortex–corner interaction are evident. The corresponding form and phasing of the instantaneous pressure fields are strongly dependent upon the nature of the vortex–corner interaction, though the maximum amplitude on the top and front faces is always of the same order. For certain interactions, there is separation of flow from the edge of the corner, as well as from the front face of the corner, leading to secondary-vortex formation and corresponding peaks in the local pressure fields. By integrating the instantaneous pressure fields along the top and front faces of the corner, the phasing between the respective forces is shown to exhibit varying degrees of dipole-like behaviour, depending upon the character of the incident vortex–corner interaction. Amplitudes of the corresponding moments of the pressure fields are remarkably insensitive to this interaction.