Bienvenida y bienvenido a la página de inicio de la LGAC Fuentes Alternas de Energía.
Una fuente de energía alternativa se define como la energía que proviene de una fuente que se reabastece constantemente en forma natural y que puede suplir a los tipos de energía que tradicionalmente se usan, ya sea por su menor efecto contaminante como por su posibilidad de renovación. La crisis energética actual ha cambiado la perspectiva mundial en cuanto al consumo dispendioso de energía. Como resultado de un uso indiscriminado de recursos no renovables y la creciente preocupación sobre los impactos ambientales, la inversión en el desarrollo e implementación de fuentes alternas de energía ha aumentado considerablemente en la última década. Aun cuando todavía no hay acuerdo sobre el alcance del problema del calentamiento global, asociado al incremento de emisiones de gases de efecto de invernadero, existe un consenso generalizado de que el ser humano deberá evitar el uso de combustibles fósiles como su principal fuente de energía primaria y optar por fuentes más seguras, abundantes y menos dañinas para el medio ambiente. El objetivo de esta línea de investigación es la formación de recursos humanos, altamente especializados, en aspectos teóricos, numéricos y experimentales, que incidan en el crecimiento científico de nuestro país, en áreas de investigación científica de vanguardia, relacionadas con el aprovechamiento de fuentes alternas de energía.
Tsunami generation by a seabed deformation in the presence of a viscoelastic mud
Researchers: S. Bahena-Jimenez, E. Bautista, F. Méndez
Abstract: In this work, under the assumption of linear water waves, we study tsunamis generated by a seabed deformation in the presence of viscoelastic mud. We divide the total control volume under study into a water layer, which is assumed to be an irrotational and inviscid flow, and a mud layer with viscoelastic properties that obeys a linear Maxwell rheological model. Considering that fluid layer thicknesses are of the same order of magnitude and that they are much smaller than the characteristic horizontal length of the seabed deformation, we obtain a semi-analytical solution that models the evolution of the free surface elevation. For the above limits, the fluid motion in the water layer is essentially horizontal. Passive and active tsunami generation cases are analyzed. The seabed deformation is modeled as a Heaviside step function. For an active generation case, when the mud layer thickness increases, the tsunami’s maximum amplitude decreases. For the passive generation case, the tsunami’s maximum amplitude remains constant in a finite time interval of the same order of magnitude as the characteristic time; this phenomenon does not occur for the active generation case.
Publications: Bahena-Jimenez, S., Bautista, E., & Méndez, F. (2023). Tsunami generation by a seabed deformation in the presence of a viscoelastic mud. Physics of Fluids, 35(1).
Flow measurements of jet impingement upon a semicylinder with crossflow
Researchers: A. Alvarez, C. Treviño, F. Pérez-Flores, L. Martínez-Suástegui
Abstract: In this work, time-resolved particle image velocimetry (TR-PIV) measurements have been carried out to investigate the structural features of a submerged transverse round liquid turbulent jet discharged into a confined laminar crossflow. The duct Reynolds number based on crossflow velocity is fixed at 𝑅𝑒 = 3000, and the impinging jet is directed to a semicylindrical concave surface located in one of the walls of a vertical square duct. The spatial development and flow dynamics are analyzed along several orthogonal planes parallel/perpendicular to the jet axis for jet Reynolds numbers based on the jet exit diameter of Rej = 3000, 6000 and 9000 (jet-to-crossflow velocity ratios of r = 3.27, 6.53 and 9.80), respectively. For this purpose, mean and ensemble-averaged velocity and vorticity distributions, turbulent statistics, and Reynolds shear stresses are obtained for various injection rates. Spectral analysis reveals the shedding frequencies of the wake vortices, and the pairing and breakup processes of the evolving large-scale coherent structures have been related to the measured wake Strouhal numbers. Our results indicate that due to the curvature of the target surface and the upwash of the jet impact, the size of coherent structures decreases with increase in the value of Rej. Proper orthogonal decomposition (POD) of the flow using the snapshot method is applied to extract the dominant features of the turbulent flow. It is observed that at the symmetry plane and for Rej = 3000, 6000 and 9000, the energy collected by the first two dominant eddies contribute to 14.98%, 18.68%, and 17.89% of the turbulence kinetic energy, respectively. Our results show that the evolution of the time-resolved temporal coefficients of degenerate pairs of modes (1, 2) represent the flapping motion of the jet. Moreover, the amplitude of the oscillations of the flapping jet and the complexity of the flow structure increase for increasing values of Rej.
Publications: A. Alvarez, C. Treviño, F. Pérez-Flores, L. Martínez-Suástegui, Int. J. Mech. Sci., 255 (2023) 108271.
Flow structure and impinging interactions of two confined turbulent converging jets in crossflow
Researchers: D. Matuz, C. Treviño, F. Pérez-Flores, C. Sandoval, L. Martínez-Suástegui
Abstract: In this work, time-resolved particle image velocimetry (TR-PIV) measurements are carried out to study the flow structure and impinging interactions of two confined turbulent converging jets in crossflow, with the upstream and downstream jets inclined at 20◦ and 170◦ with respect to the oncoming crossflow direction. Experiments are conducted for fixed dimensionless nozzle separation distance of 𝑠 = 𝐿∕𝐷 = 3, fixed dimensionless nozzle-to-target surface distance of 𝐻∕𝐷 = 6.73, fixed duct Reynolds number of 𝑅𝑒 = 3500 and two jets’ Reynolds numbers of 𝑅𝑒𝑗 = 3000 and 6000 that correspond to jets’-to-crossflow velocity ratios of 𝑟𝑗 = 3.45 and 6.91, respectively. Flow visualization images showing ensemble-averaged and instantaneous flow distributions and turbulent characteristics including Reynolds stresses and turbulence intensities for equal and non-equal discharge velocities of the jets are presented on several orthogonal planes of the test section. The swirling strength criterion has been employed to identify coherent structures, and cross spectral analysis of the fluctuating velocity signals detecting subharmonic and harmonic sideband frequencies identify the merging and breakup interactions of the evolving coherent structures. The snapshot proper orthogonal decomposition technique (POD) has been applied to extract the dominant vortical structures and to quantify their relative and cumulative energy contributions to the total kinetic energy fluctuation. The spatial structure of the main four POD modes and the temporal projections of these POD coefficients have been explored to understand the spatio-temporal characteristics of the dominant turbulent fluctuations and their spectral characteristics. Our results show the effect of the velocity ratios on the jets’ trajectories, penetration, spreading characteristics, crossflow entrainment through the inner and outer shear layers, transverse velocity decay, size of the converging region and location of the combining point. In addition, the dimensionless shedding frequencies of the oscillating combined jet, the developing wall jets and wake vortices have been obtained. Furthermore, it has been shown that for all values of the jets’ velocity ratios employed in this study, a recirculation region does not develop in the converging region.
Publications: D. Matuz, C. Treviño, F. Pérez-Flores, C. Sandoval, L. Martínez-Suástegui, Int. J. Heat Mass Tran., 218 (2024) 124723.
