Browsing by Author "Brevis Vergara, Wernher Ariel"
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- ItemA simple approach for effective CFD simulation of turbulent pipe transport of shear-thinning, power-law fluids(2026) Soto Sáez, Jorge Ignacio; Messa, G. V.; Malin, M. R.; Brevis Vergara, Wernher ArielThis study presents a simple, efficient approach for the CFD simulation of turbulent pipe transport of shear-thinning, power-law fluids. The method is developed within the Newtonian-based Reynolds-Averaged Navier-Stokes (RANS) framework, and it relies on a modification to the Reynolds-averaged apparent viscosity function to compensate for errors induced by the non-decomposition of the instantaneous apparent viscosity, as well as for the use of turbulence models developed for Newtonian fluids. Specifically, the Reynolds-averaged apparent viscosity switches from a power law to a logarithmic function for averaged shear rates below a threshold value, called the “critical shear rate”, which becomes a calibration parameter of the model. The new framework was tested against DNS data reported in the literature for different pipe-flow conditions, covering combinations of flow index and friction Reynolds number , as well as against well-established correlations for the friction factor, with the analysis extended to cases up to and . The analysis was conducted by employing three different turbulence models, namely Lam-Bremhorst k-ε, two-layer k-ε, and k-ω SST, which all rely on a low-Reynolds number treatment to obtain a detailed flow description in the near-wall region. The proposed approach appears attractive from an engineering standpoint, as it allows obtaining reasonably accurate prediction of main features of turbulent pipe transport of shear-thinning, power-law fluids, with a simple mathematical formulation and a robust and easy-to-converge character that can make a difference for the application to more complex flows.
- ItemAir Bubbles as an Admixture for Printable Concrete: A Review of the Rheological Effect of Entrained Air(2022) Eugenin, C.; Navarrete, I.; Brevis Vergara, Wernher Ariel; Lopez, M.; CEDEUS (Chile)
- ItemEffect of supplementary cementitious materials on viscosity of cement-based pastes(2022) Navarrete, I.; Kurama, Y.; Escalona, N.; Brevis Vergara, Wernher Ariel; Lopez, M.; CEDEUS (Chile)
- ItemEffects of inflow conditions on low mass-damping cylinder subjected to vortex-induced vibrations(2022) Mella, D.; Brevis Vergara, Wernher Ariel; Susmel, L.
- ItemElucidating the importance of sediment avalanches in scour at obstacles(2022) Soto, J.; Link, O.; Brevis Vergara, Wernher Ariel
- ItemErosion by turbulence: Discovering the counter-wise vortex events and their effect on wear(2023) Espinoza-Jara, A.; Walczak, M.; Brevis Vergara, Wernher Ariel; Messa, G.V.
- ItemErosion under turbulent flow: a CFD-based simulation of near-wall turbulent impacts with experimental validation(2022) Espinoza-Jara, A.; Walczak, M.; Molina, N.; Jahn, W.; Brevis Vergara, Wernher Ariel
- ItemExperimental insights into sweep-induced mechanism of erosive wear in a straight pipe section with turbulent slurry flow(2025) Espinoza Jara, Ariel Orlando; Walczak, Magdalena; Vittorio Messa, Gianandrea; Brevis Vergara, Wernher Ariel; Pascone, Alessandro; Tedeschi, CristinaReliable design and operation of slurry handling systems are critical in industries such as mining. This study examines erosion due to solid particle impacts in a straight pipe section, introducing the concept of “turbulent erosive wear”. Ultrasound particle image velocimetry (UPIV) is used to observe flow at the surface of a ductile target (copper). Experiments are conducted at flow velocities of 1.97 and 2.15 m/s, with particle sizes of 500 and 700m. Sweep events are identified, and their frequency, intensity, and duration are analysed using wavelet analysis. The results show that velocity impacts of solid particles during sweeps correlate with the geometry of wear scars. Turbulent erosive wear is linked to a characteristic threshold value of impact velocity. This value provides a measurable parameter to enhance predictive modelling and material selection for pipeline design.
- ItemMagnetohydrodynamic Wave Mode Identification in Circular and Elliptical Sunspot Umbrae: Evidence for High-order Modes(2022) A. B. Albidah; V. Fedun; A. A. Aldhafeeri; I. Ballai; Brevis Vergara, Wernher Ariel; D. B. Jess; J. Higham; M. Stangalini; S. S. A. Silva; G. Verth
- ItemMagnetohydrodynamic Wave Modes of Solar Magnetic Flux Tubes with an Elliptical Cross Section(2021) Aldhafeeri, A.A.; Verth, G.; Brevis Vergara, Wernher Ariel; Jess, D.B.; McMurdo, M.; Fedun, V.
- ItemModels of bed-load transport across scales: turbulence signature from grain motion to sediment flux(2023) Escauriaza, C.; González, C.; Williams, M.E.; Brevis Vergara, Wernher Ariel
- ItemModification of modal characteristics in wakes of square cylinders with multi-scale porosity(2021) J. E. Higham; A. Vaidheeswaran; Brevis Vergara, Wernher Ariel; F. C. G. A. Nicolleau; J. Marlow
- ItemProper orthogonal and dynamic mode decomposition of sunspot data: POD and DMD of Sunspot Data(2021) Albidah, A.B.; Brevis Vergara, Wernher Ariel; Fedun, V.; Ballai, I.; Jess, D.B.; Stangalini, M.; Higham, J.; Verth, G.
- ItemSingle cylinder subjected to vortex-induced vibrations: Estimating cyclic stresses for fatigue assessment(2020) Mella, D.; Brevis Vergara, Wernher Ariel; Susmel, L.
- ItemThe Temporal and Spatial Evolution of Magnetohydrodynamic Wave Modes in Sunspots(2023) A. B. Albidah; V. Fedun; A. A. Aldhafeeri; I. Ballai; D. B. Jess; Brevis Vergara, Wernher Ariel; J. Higham; M. Stangalini; S. S. A. Silva; C. D. MacBride; G. Verth
- ItemUltrasound particle image velocimetry in turbulent particle-laden flows: Line density correction with experimental validation(2025) Bone Fonte, Edwin Giovanny; Espinoza Jara, Ariel Orlando; Walczak, Magdalena Marta; Brevis Vergara, Wernher ArielThedynamics of solid particles in turbulent flows are crucial for industrial applications such as transport of mining slurries, where particle trajectories are essential for predicting erosive wear. This study evaluates the use of ultrasound particle image velocimetry (UPIV) to measure the velocity field of glass beads (250–300 µm; 1, 2, 3 wt.%) in a controlled turbulent setting (slurry pot, Stokes number 1.21–5.66, Reynolds number 1.75×105) validating the results against optical PIV measurements. A line density correction is developed to address the errors caused by electronic sweeping and transducer artifacts, both inherent to UPIV. The standard error in transversal velocity is reduced by 21.6%. Although UPIV operates at a lower frame rate (335 fps), wavelet analysis validates its effectiveness in capturing flow structures relevant to erosive wear. These findings highlight UPIV’s potential to advance the study of flow dynamics in opaque media.
- ItemWhen, what and how image transformation techniques should be used to reduce error in Particle Image Velocimetry data?(2019) Higham, J.E.; Brevis Vergara, Wernher Ariel