Towards strongly-coupled simulations of wall-bounded turbulent flows past defect-embedded phononic subsurfaces

Abstract: Passive flow control using phononic subsurfaces (PSubs) has shown potential for modifying near-wall turbulence in wall-bounded turbulent flows. Recent numerical studies of fluid–structure interaction (FSI) using defect-embedded phononic subsurfaces (D-PSubs) have demonstrated that these architected structures provide a narrow-band structural response to broadband turbulent forcing, acting as a frequency-selective compliant interface whose coupling with the flow gives rise to new emergent frequencies. The resulting PSub–turbulence interactions yield measurable drag-reduction trends through mechanisms that include reorganization of near-wall coherent streak and vortex structures and the formation of localized regions of turbulence attenuation and amplification. While these studies have provided significant physical insight, they have relied on weakly coupled formulations in which the flow and structure are advanced sequentially. Such formulations capture the leading-order interaction mechanisms but leave open the question of whether the observed frequencies, amplitude envelopes, and turbulence modulation trends persist under a fully coupled framework that simultaneously enforces the nonlinear no-slip constraint between the turbulent flow and the deforming D-PSub. Toward this aim, we propose to perform fully coupled high-fidelity simulation of turbulent channel flow past an array of D-PSubs using our parallelized immersed-boundary framework. In this abstract, we outline the strongly-coupled FSI formulation and the additional low-dimensional sub-iterations that arise from imposing a strict no-slip constraint. Initial qualitative validations demonstrate correct implementation of the framework, and preliminary computations of benchmark problems are shown as proof-of-concept. For the full manuscript, we propose to perform an extensive validation of the strongly-coupled framework, including a systematic assessment of its stability and accuracy for turbulent flow–deforming body interactions. The framework will subsequently be used to simulate D-PSub–turbulent flow interactions in the configuration of our prior weakly coupled study, and a systematic comparison will be presented to assess the persistence of the key interaction mechanisms under full coupling.

Citation: S. Balasubramanian, D. Beckers, C. T. Lin, V. Ramakrishnan, K. H. Matlack, A. Goza, H. J. Bae, "Towards strongly-coupled simulations of wall-bounded turbulent flows past defect-embedded phononic subsurfaces", AIAA SciTech Forum 2027, Orlando, FL, January 11–15, 2027
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