The development of accurate methodologies for a thorough comprehension of the erosion phenomenon is a challenging and necessary task. This study entailed an exhaustive analysis, incorporating empirical data obtained from an experiment involving the impingement of a sand and water jet on a submerged stainless-steel plate and numerical simulations, employing the Oka Erosion model that was compilated in OpenFOAM. The primary focus of this study was to generate W-shaped profiles delineating the impingement zone, derived both from experimental observations and the developed numerical model. This comparative approach facilitated a robust evaluation of the model’s efficacy in replicating erosion patterns. The outcomes of this analysis revealed a concurrence between the experimental and simulated erosion contours, affirming the model’s proficiency in representing erosion phenomena. Nevertheless, a minor discrepancy was noted, characterized by a slight underestimation of erosion rate and thickness loss. Furthermore, the investigation unveiled a noteworthy time-dependent trend in mass loss from the experimental data denoting a pseudo stabilization of the erosion rate across the time. This research contributes to the refinement of erosion modeling parameters and underscores the nature of time-dependent erosion behavior, a pivotal consideration for optimizing material durability.

Hydraulic erosion from suspended sediment is a major degradation mechanism in Francis turbines of sediment-laden rivers, especially in Andean hydropower plants. This study presents a Python3.9-based computational tool integrating the empirical Oka erosion model within a Lagrangian particle tracking framework, coupled to single-phase CFD in OpenFOAM 10. The novelty lies in a reduced-domain approach that omits the spiral casing and replicates its particle-induced swirl via a custom algorithm, lowering meshing complexity and computational cost while preserving erosion prediction accuracy. The method was applied to a full-scale Francis turbine at the San Francisco hydropower plant in Ecuador (nominal discharge 62.4 m³/s, rated output 115 MW, rotational speed 34.27 rad/s), operating under volcanic and erosive sediment loads. Maximum erosion rates reached ~1.2 × 10⁻⁴ mm³/kg, concentrated on runner blade trailing edges and guide vane pressure sides. Impact kinematics showed most collisions at near-normal angles (85°–98°, peak at 92°) and 6–9 m/s velocities, with rare 40 m/s impacts causing over 50× more loss than average. The workflow identifies critical wear zones, supports redesign and coating strategies, and offers a transferable, open-source framework for erosion assessment in turbines under diverse sediment-laden conditions.

The structural integrity and surface quality of parts produced using traditional fused deposition modeling depend on factors such as layer height, filament and build orientation, print speed, nozzle temperature, and, crucially for this study, both planar and non-planar slicing. Recent research on non-planar slicing techniques has shown significant improvements in surface smoothness and mechanical properties. Key approaches include non-planar slicing for 3-axis printers, adaptive slicing to optimize material placement in critical areas, and post-processing. However, current studies lack a comprehensive method for parameterizing filament direction across both planar and non-planar layers. This work presents an approach to generate optimal trajectories for planar and non-planar layers using contours derived from level set functions. The methodology demonstrates the advantages of non-planar printing, particularly with a filament orientation of 30° for inclined surfaces, ensuring better surface quality, uniformity, and structural integrity. This emphasizes the importance of trajectory planning and filament orientation in achieving high-quality prints on inclined geometries. This research highlights the necessity of a methodology that tailors filament paths based on the load-bearing requirements of each part, demonstrating its potential to enhance surface quality and structural performance, and further the advancement of the 3D printing industry.

This study investigates how three technical factors—steering wheel tilt, torque, and cabin vibration frequency—affect driver posture. Heavy-truck drivers often suffer from musculoskeletal disorders (MSDs), mainly due to poor cabin ergonomics and prolonged postures during work. In countries like Ecuador, making major structural changes to cabin design is not feasible. These factors were identified through video analysis and surveys from drivers at two Ecuadorian trucking companies. An experimental system was developed using a simplified cabin to control these variables, while posture and muscle activity were recorded in 16 participants using motion capture, inertial sensors, and electromyography (EMG) on the upper trapezius, middle trapezius, triceps brachii, quadriceps muscle, and gastrocnemius muscle. The test protocol simulated key truck-driving tasks. Data were analyzed using ANOVA (${\displaystyle p<0.05}$), with technical factors and mass index as independent variables, and posture metrics as dependent variables. Results showed that head mass index significantly affected head abduction–adduction (${\displaystyle -}$8.12 to ${\displaystyle -}$2.18°), and spine mass index influenced spine flexion–extension (${\displaystyle -}$0.38 to 6.99°). Among technical factors, steering wheel tilt impacted trunk flexion–extension (${\displaystyle -}$13.56 to 16.99°) and arm rotation (${\displaystyle -}$31.1 to 19.7°). Steering wheel torque affected arm rotation (${\displaystyle -}$30.49 to ${\displaystyle -}$6.77°), while vibration frequency influenced forearm flexion–extension (3.76 to 16.51°). EMG signals showed little variation between muscles, likely due to the protocol’s short duration. These findings offer quantitative support for improving cabin ergonomics in low-resource settings through targeted, cost-effective design changes.

This study compares the hydraulic performance of two centrifugal-pump impellers operating in pump and pump-as-turbine (PAT) modes: a reverse-engineered impeller obtained from a commercial pump by 3D scanning and an impeller developed through a preliminary analytical sizing procedure. Both configurations were evaluated under the same computational framework using OpenFOAM, the Multiple Reference Frame approach, and the k-omega SST turbulence model. Hydraulic performance was assessed through efficiency, pressure, velocity, and turbulent-dissipation fields, complemented by velocity-triangle and parametric sensitivity analyses. The reverse-engineered impeller achieved efficiencies of 90.50% in pump mode and 67% in PAT mode, compared with 79.17% and 50%, respectively, for the analytically designed impeller. Internal-flow analysis indicated that the reverse-engineered geometry produced more uniform velocity and pressure distributions and less extensive turbulent-dissipation regions. Velocity-triangle analysis indicated that its inlet blade angle increases the incidence mismatch in pump mode but reduces residual tangential velocity in PAT operation, favoring angular-momentum transfer. Sensitivity analysis indicated that the dominant geometric parameters depend on the operating direction. The analytical procedure is therefore interpreted as a preliminary sizing approach rather than a validated dual-mode optimization method. Overall, the results indicate that reversible impeller design should consider both operating directions and subsequent CFD-based refinement.