Flow reorganization and Curle-related source redistribution by a boxfish-inspired fairing in confined high-blockage elevator flow

An ultra-high-speed elevator operating in a narrow hoistway generates a confined high-blockage flow, with windward compression, annular-gap acceleration, leeward separation, wake development, and wall-pressure fluctuations that govern aerodynamic forces and aeroacoustic radiation. In this study, the elevator car is treated as a confined bluff body, and a boxfish-inspired multi-curvature fairing (bionic configuration) is constructed from the leading-edge contour of a boxfish snout. Its performance is compared with a no-fairing baseline (none configuration) and an arc-shaped reference fairing (general configuration). A staged turbulence-modeling strategy combining the renormalization-group k−ε model and large-eddy simulation is used to resolve the unsteady flow field, and Curle's acoustic analogy is used to map wall-pressure fluctuations to surface sound pressure level (SPL), far-field SPL, and propagation attenuation along the hoistway. The results show that the bionic configuration retains mechanisms reported for boxfish-inspired bodies in free-stream flow, including smooth curvature transition, weakened separation, wake contraction, and improved pressure recovery. Under confinement, however, the dominant mechanism shifts toward coordinated regulation of annular-gap shear-layer feeding, confined-wake contraction, and leeward pressure recovery. Relative to the none configuration, the bionic configuration reduces drag by 38.6%–55.7% and provides an additional drag reduction of 12.9%–19.8% over the general configuration. A wall-pressure-fluctuation-based Curle-related equivalent dipole-source indicator shows that the dominant source regions of the none configuration are concentrated in the rear shoulder transition and leeward base regions, which together contribute more than 97% of the total indicator. The general configuration reduces the total source indicator to approximately 19.0% of that of the none configuration, whereas the bionicionic configuration further reduces it to approximately 0.29%. Correspondingly, the bionic configuration reduces the mean surface SPL by 22.8 and 10.8 dB relative to the none and general configurations, respectively. These results demonstrate that the boxfish-inspired fairing modifies aerodynamic and aeroacoustic responses by reorganizing the annular-gap shear layer, leeward wake topology, and Curle-related equivalent dipole-source indicator distribution in confined high-blockage flow.