Toward Identification and Reconstruction of Vortical Structures Using Near-Wall Pressure Distribution

It is well known that vortex cores are regions of low pressure; however, the influence of near-wall vortical structures on wall pressure is yet to be understood in adequate detail. Previous experimental observations suggest that there is a correlation between the wall pressure distribution and steady streamwise vortices near the wall, such as those produced by a vortex generator. Gaining a better understanding of this relationship is crucial for creating novel flow control solutions. We aim to extend the existing understanding to unsteady flow involving different kinds of vortical structures and explore the possibility of reconstructing a time-dependent vorticity field using only wall pressure measurements. Such a reconstruction would allow for precise targeting of specific vortical structures or mechanisms in technologically relevant scenarios, such as transition mitigation or stall alleviation. Direct numerical simulations are performed for a set of prototypical cases, including steady and unsteady streamwise vortices, a bluff body placed outside a laminar boundary layer, and roughness-induced transition. The effect of size, nature, and location of the vortical structure, unsteadiness, and the effect of wall shear on the pressure-vorticity relationship are analyzed.