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The results of particle image velocimetry in the near-wake of a rectangular wing section with the leading edge tubercles of various lengths and an airfoil, developed by the National Advisory Committee for Aeronautics (NACA 0012), are presented. The main attention is paid to the study of the influence of the tubercle length on the features of the formation of the flow in the near-wake of the wing model. Based on the reference case of a wing model with a chord of 100 mm and a span–chord ratio of 2, the influence of four tubercle lengths (5, 15, 25, and 35 mm) of tubercles, located symmetrically relative to the chord of the wing airfoil, was studied within the interval of chord-based Reynolds number Reb = 3.65 × 104–2.36 × 105 and for two angles of attack α = 0° (no separation case) and α = 9.5° (massive laminar stall). In order to understand the effect of the regular structure of counter-rotating vortex pairs, formed by the tubercles and its further interaction with the boundary layer of the wing, measurements were performed in two sections of the near-wake perpendicular to the wingspan: in the plane of symmetry of the tubercle and in the middle plane between the pair of neighbor tubercles. It has been experimentally confirmed that even at α = 0°, the tubercles are the source of additional drag, estimated at 3%–18%. It was also found that even the shortest tubercles of 5 mm are, apparently, the most rational in terms of their both aerodynamic and weight efficiency. [ABSTRACT FROM AUTHOR]

The co-occurrence of nutrients and pharmaceuticals and personal care products (PPCPs) in sewage effluent can degrade water quality of the receiving watersheds. This study investigated the simultaneous removal of excess nutrients and PPCP contaminants by developing a novel woodchip bioreactor and biochar (B 2 ) treatment system. The result revealed that woodchip bioreactors could effectively remove nitrate via a denitrification process and adsorb some PPCPs. Biochar as a secondary treatment system significantly reduced the concentrations of PPCPs and dissolved reactive phosphorus (DRP) (p < 0.05), compared to the woodchip bioreactor. The removal efficiencies of all targeted contaminants by the B 2 system were evaluated using various hydraulic retention times (HRTs) and biochar types (pelletized versus granular biochar). Longer HRTs and smaller biochar particles (granular biochar) could enhance the removal efficiencies of targeted contaminants. Average contaminant removals were 77.25 % for nitrate-N, 99.03 % for DRP, 69.51 % for ibuprofen, 73.65 % for naproxen, 91.09 % for sitagliptin, and 96.96 % for estrone, with woodchip bioreactor HRTs of 12 ± 1.4 h and granular biochar HRTs of 2.1 ± 0.1 h. Notably, the second-stage biochar systems effectively mitigated by-products leaching from woodchip bioreactors. The presence of PPCPs in the woodchip bioreactors enriched certain species, such as Methylophilus (69.6 %), while inhibiting other microorganisms and reducing microbial community diversity. Furthermore, a scaled-up B 2 system was analyzed and assessed, indicating that the proposed engineering treatment system could provide decades of service in real-world applications. Overall, this study suggests that the B 2 system has promising applications for addressing emerging and conventional contaminants., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)