The placement of artificial reefs (ARs) significantly influences local hydrodynamics and nutrient transport, both of which are crucial for enhancing marine ecosystems and improving marine habitats. Large eddy simulations (LESs) are performed to study the flow field around a cuboid artificial reef (CAR) with three inflow angles ($\alpha$ = 0°, 45°, and 90°). The numerical method is successfully validated with experimental data, and a reasonable grid resolution is chosen. The results demonstrate that the case with an inflow angle of 45° exhibits superior flow field performance, including the largest recirculation bubble length and the maximum volumes for both the upwelling and wake regions. Stronger turbulence is also observed around the CAR at this inflow angle, attributed to the intensified shear layer. The instantaneous flow features torn horseshoe vortices and rollers shed from the shear layer, which further develop into hairpin vortices.

For steel box girder of cable-stayed bridge, which using incremental launching method, during the launching process, structural system and boundary conditions were changing, structure mechanical behaviors were complex. It was necessary to conduct a comprehensive analysis on internal force and deformation of the whole structure during the launching process. Took a cable-stayed bridge with single tower, double cable planes and steel box girder in China as an example; finite element software MIDAS Civil 2010 was used to establish a model for steel box girder, simulation analysis of the entire incremental launching process was carried out. Variation rules and envelopes of the internal force, stress, deformation and support reaction were obtained. The result showed that: the maximum value of positive bending moment after launching complete was 60% of the maximum value of positive bending moment during the launching process. The maximum value of negative bending moment after launching complete was 78% of the maximum value of negative bending moment during the launching process.

Lateral cavities along coastlines strongly influence sedimentary morphology and ecological processes by modifying local flow dynamics. This study employed high-resolution large-eddy simulation to investigate flow structures and momentum exchange mechanisms in a semi-circular lateral cavity driven by longshore currents. Model validation against experimental data confirmed the LES’s capability to capture both recirculating flow and turbulent structures accurately. The impact of Reynolds number was examined across three cases ($Re$ = 12,000, 17,000, and 22,000). From $Re$ = 12,000 to 17,000, a significant upstream shift of the primary vortex core occurred, accompanied by stronger shear layer turbulence and intensified secondary vortices. Between $Re$ = 17,000 and 22,000, the flow features stabilized, indicating a transition toward quasi-equilibrium. These changes enhanced vertical momentum transfer and turbulence production within the cavity. Spectral analysis revealed dominant KH frequencies governing periodic momentum exchange and indicating a transition from viscosity-damped upstream turbulence to fully developed shedding downstream.

Large-eddy simulations (LESs) were performed to investigate turbulent flow past a triangular baffle in a culvert at three orientations of 45°(C45), 90°(C90), and 135°(C135). The Reynolds and Froude numbers were fixed at Re=70 000 and Fr=0.376, respectively. The LES approach was first validated against laboratory measurements of mean velocity and turbulence intensity, showing good agreement. The time-averaged velocity fields indicate that the blockage effect decreases with the increasing baffle angle, with high-velocity regions concentrated near the baffle in C135. Flow separation produces recirculation zones upstream and downstream of the baffle; the upstream recirculation disappears in C135, while the downstream zone shortens and weakens with angle and elevation. Reynolds shear stress and turbulent kinetic energy contours confirm that turbulence is strongest in the shear layer and most intense in C135. Instantaneous flow structures identified by the Q-criterion highlight coherent vortices and strong vortex shedding, particularly at larger baffle angles. Quadrant analysis shows a transition from a balanced distribution of turbulent events in C45 to dominant ejection–sweep interactions in C90 and C135, accompanied by increased fluctuation intensity. Spectral analysis reveals vortex-shedding frequencies of 0.196–0.296 Hz, corresponding to Strouhal numbers of 0.055–0.083, which increase with baffle angle.