In this paper, the D3Q19 multiple-relaxation-time (MRT) lattice Boltzmann method (LBM) for large eddy simulation (LES) was employed to optimize the shape of the vortex generator in a triangular vortex flowmeter. The optimization process focused on the vortex shedding frequency, lift force per unit area, and symmetry of the vortex street. The optimal shape of the vortex generator was determined to feature a 180° incoming flow surface, a concave arc side with a curvature radius of 25 mm, and a fillet radius of 4 mm at the end. Numerical simulations revealed that the optimized vortex generator achieves a 2.72~13.8% increase in vortex shedding frequency and a 17.2~53.9% reduction in pressure drop and can adapt to the flow conditions of productivity fluctuations (6.498 × 10⁵ ≤ Re ≤ 22.597 × 10⁵) in the gas well production. The results demonstrated significant advantages, including low pressure loss, minimal secondary vortex generation, high vortex shedding frequency, and substantial lift force. These findings underscore the robustness and efficiency of the LBM-LES method in simulating complex flow dynamics and optimizing vortex generator designs.

Fuhe River is the second largest river that flows into Poyang Lake, the largest freshwater lake in China. With rapid socioeconomic development, heavy metal pollution in its sediments has become increasingly severe. To clarify the distribution and sources of heavy metals in the Fuhe River Basin, sediment samples were collected from the mainstream and major tributaries in July 2021, and the contents of Cr, Mn, Ni, Cu, Zn, Cd, Pb, U, Zr and Pb isotopes in the sediments were measured. Results showed that Zr, U, and Cd contents were higher in the upper reaches; Cr was highest in the lower reaches and Ni, Cu, Zn and Pb contents peaked at the estuary of the Yihuang River (a tributary). The analyses of the multivariate statistical methods (MVSM), including Absolute Principal Component Score-Multiple Linear Regression and Positive Matrix Factorization, principal component analysis and correlation analysis, revealed that Mn, Cu, Zn and Pb were mainly from industrial activities, Cd, U and Zr were from natural rock weathering, Cr came from agricultural activities, and Ni originated from the combined pollution of industry and agriculture. Pb isotope signal highlighted that Pb in the sediments was mainly associated with industrial activities. The Pollution Load Index highlighted the most severe pollution at this estuary, while the Geo-accumulation Index indicated prominent Cd pollution (twice the background value). The Potential Ecological Risk Index and Human Health Risk Assessment Model indicated that the risks of sediments in the middle reaches are greater. These findings help to deeply understand the cycle of river pollutants and are also helpful for the treatment of river pollution.