Numerical Study of Wave Forces on Crown Walls of Mound Breakwaters with Parapets

[EN] The influence of parapets on crown walls of mound breakwaters on wave forces has not been extensively analyzed in the literature. In this study, numerical experiments were carried out using the open-source platform OpenFOAM(R) to evaluate the influence of nine crown wall geometries with and without parapets. The OpenFOAM(R) model was validated with laboratory experiments. Dimensionless horizontal forces and overturning moments due to horizontal forces increase when there is a parapet. Dimensionless up-lift forces provide similar results, regardless of the existence of a parapet. Crown walls with parapets increase the horizontal wave forces and overturning moments due to horizontal wave forces by a factor of two.This research was funded by (1) Universitat Politecnica de Valencia (Grant SP20180111, Primeros Proyectos de Investigacion (PAID-06-18), Vicerrectorado de Investigacion, Innovacion y Transferencia de la Universitat Politecnica de Valencia) and (2) Spanish Ministerio de Ciencia, Innovacion y Universidades (Grant RTI2018-101073-B-I00).Molines, J.; Bayón, A.; Gómez-Martín, ME.; Medina, JR. (2020). Numerical Study of Wave Forces on Crown Walls of Mound Breakwaters with Parapets. Journal of Marine Science and Engineering. 8(4):1-15. https://doi.org/10.3390/jmse8040276S11584Molines, J., Bayon, A., Gómez-Martín, M. E., & Medina, J. R. (2019). Influence of Parapets on Wave Overtopping on Mound Breakwaters with Crown Walls. Sustainability, 11(24), 7109. doi:10.3390/su11247109Martinelli, L., Ruol, P., Volpato, M., Favaretto, C., Castellino, M., De Girolamo, P., … Sammarco, P. (2018). Experimental investigation on non-breaking wave forces and overtopping at the recurved parapets of vertical breakwaters. Coastal Engineering, 141, 52-67. doi:10.1016/j.coastaleng.2018.08.017Nørgaard, J. Q. H., Andersen, T. L., & Burcharth, H. F. (2013). Wave loads on rubble mound breakwater crown walls in deep and shallow water wave conditions. Coastal Engineering, 80, 137-147. doi:10.1016/j.coastaleng.2013.06.003Molines, J., Herrera, M. P., & Medina, J. R. (2018). Estimations of wave forces on crown walls based on wave overtopping rates. Coastal Engineering, 132, 50-62. doi:10.1016/j.coastaleng.2017.11.004Van Gent, M. R. A., & van der Werf, I. M. (2019). Influence of oblique wave attack on wave overtopping and forces on rubble mound breakwater crest walls. Coastal Engineering, 151, 78-96. doi:10.1016/j.coastaleng.2019.04.001Castellino, M., Sammarco, P., Romano, A., Martinelli, L., Ruol, P., Franco, L., & De Girolamo, P. (2018). Large impulsive forces on recurved parapets under non-breaking waves. A numerical study. Coastal Engineering, 136, 1-15. doi:10.1016/j.coastaleng.2018.01.012Issa, R. . (1986). Solution of the implicitly discretised fluid flow equations by operator-splitting. Journal of Computational Physics, 62(1), 40-65. doi:10.1016/0021-9991(86)90099-9Patankar, S. ., & Spalding, D. . (1972). A calculation procedure for heat, mass and momentum transfer in three-dimensional parabolic flows. International Journal of Heat and Mass Transfer, 15(10), 1787-1806. doi:10.1016/0017-9310(72)90054-3Jacobsen, N. G., van Gent, M. R. A., Capel, A., & Borsboom, M. (2018). Numerical prediction of integrated wave loads on crest walls on top of rubble mound structures. Coastal Engineering, 142, 110-124. doi:10.1016/j.coastaleng.2018.10.004Jensen, B., Jacobsen, N. G., & Christensen, E. D. (2014). Investigations on the porous media equations and resistance coefficients for coastal structures. Coastal Engineering, 84, 56-72. doi:10.1016/j.coastaleng.2013.11.004Hirt, C. ., & Nichols, B. . (1981). Volume of fluid (VOF) method for the dynamics of free boundaries. Journal of Computational Physics, 39(1), 201-225. doi:10.1016/0021-9991(81)90145-5Berberović, E., van Hinsberg, N. P., Jakirlić, S., Roisman, I. V., & Tropea, C. (2009). Drop impact onto a liquid layer of finite thickness: Dynamics of the cavity evolution. Physical Review E, 79(3). doi:10.1103/physreve.79.036306Jacobsen, N. G., van Gent, M. R. A., & Wolters, G. (2015). Numerical analysis of the interaction of irregular waves with two dimensional permeable coastal structures. Coastal Engineering, 102, 13-29. doi:10.1016/j.coastaleng.2015.05.004Higuera, P., Lara, J. L., & Losada, I. J. (2014). Three-dimensional interaction of waves and porous coastal structures using OpenFOAM®. Part II: Application. Coastal Engineering, 83, 259-270. doi:10.1016/j.coastaleng.2013.09.002Higuera, P., Lara, J. L., & Losada, I. J. (2013). Realistic wave generation and active wave absorption for Navier–Stokes models. Coastal Engineering, 71, 102-118. doi:10.1016/j.coastaleng.2012.07.002Higuera, P., Lara, J. L., & Losada, I. J. (2013). Simulating coastal engineering processes with OpenFOAM®. Coastal Engineering, 71, 119-134. doi:10.1016/j.coastaleng.2012.06.002Higuera, P., Lara, J. L., & Losada, I. J. (2014). Three-dimensional interaction of waves and porous coastal structures using OpenFOAM®. Part I: Formulation and validation. Coastal Engineering, 83, 243-258. doi:10.1016/j.coastaleng.2013.08.010Bayon-Barrachina, A., & Lopez-Jimenez, P. A. (2015). Numerical analysis of hydraulic jumps using OpenFOAM. Journal of Hydroinformatics, 17(4), 662-678. doi:10.2166/hydro.2015.041Bayon, A., Valero, D., García-Bartual, R., Vallés-Morán, F. ​José, & López-Jiménez, P. A. (2016). Performance assessment of OpenFOAM and FLOW-3D in the numerical modeling of a low Reynolds number hydraulic jump. Environmental Modelling & Software, 80, 322-335. doi:10.1016/j.envsoft.2016.02.018Bayon, A., Toro, J. P., Bombardelli, F. A., Matos, J., & López-Jiménez, P. A. (2018). Influence of VOF technique, turbulence model and discretization scheme on the numerical simulation of the non-aerated, skimming flow in stepped spillways. Journal of Hydro-environment Research, 19, 137-149. doi:10.1016/j.jher.2017.10.002Romano, A., Bellotti, G., Briganti, R., & Franco, L. (2015). Uncertainties in the physical modelling of the wave overtopping over a rubble mound breakwater: The role of the seeding number and of the test duration. Coastal Engineering, 103, 15-21. doi:10.1016/j.coastaleng.2015.05.00

CFD Model of a Molten Salt Tank with Integrated Steam Generator

Abstract For each solar technology the dispatchable CSP plant scheme that maximizes the solar to electrical energy conversion and minimizes the costs associated to such transformation is searched. In recent years double tank TES systems are evolving towards more simple configurations of a single tank [1] , [2] , [3] , also known as thermocline tank TES systems and, even going beyond, there are already thermocline tanks in process of development where the steam generator (SG) is integrated into the storage tank (European project OPTS). A prototype with integrated SG has been erected for testing purpose in the Casaccia Research Centre of ENEA (Italy) [4] . The model presented in this paper reproduces the experimental data of such prototype using the CFD commercial code STAR-CCM + [5] . Unlike very few published until now [6] . The simulated system account for molten salts behavior, not only for the bulk molten salts, but also for the circulation of the molten salts inside the SG (with three steam coils). The molten salts move by induced natural convection and the steam temperatures and pressures are up to ∼500° C/40 bar. Temperature gauges situated in the bulk and the molten salts mass flow inside the SG are the main variables considered for validating the model. From the numerical point of view is a transient simulation and the model is 2D-axisymmetric. The required features of the system mesh and the physical models used are presented in this work

Paso Vanoli: una instalación del Holoceno tardío en valles fluviales del sudoeste bonaerense

En este trabajo se presentan los estudios realizados sobre la colección arqueológica del sitio Paso Vanoli, conservada en el Dpto. de Humanidades de la UNS. Los trabajos de campo fueron llevados a cabo en la década de 1970 por la Lic. Pérez Amat. Paso Vanoli es un vado en el valle inferior del arroyo Napostá en el ejido urbano de Bahía Blanca (38º 40´S; 62º 13´O), provincia de Buenos Aires. Es un sitio en estratigrafía, emplazado sobre un médano, en la margen derecha del arroyo. La colección está integrada por artefactos líticos, cerámica, materiales faunísticos y restos óseos humanos. En este trabajo se presenta un fechado radiocarbónico de ca. 700 años AP y se informan los datos relacionados con las arqueofaunas y la tecnología. Se discute el abastecimiento de recursos líticos, la variabilidad artefactual y la subsistencia. Se propone que el sitio fue una base residencial vinculada con un sector de inhumaciones espacialmente segregado. Este sitio aporta información novedosa sobre los circuitos de movilidad en el sudoeste bonaerense durante el Holoceno tardío final.This paper presents the studies performed on an archaeological collection from Paso Vanoli site, housed at the Departamento Humanidades, UNS. Field works were carried out in the late 1970´s by Lic. Pérez Amat. Paso Vanoli is a ford in the lower Arroyo Napostá (Napostá Stream) in the area of urban common land of Bahía Blanca (38º 40´S; 62º 13´O), in Buenos Aires Province. It is a stratigraphic site located on a dune on the right bank of the stream. The collection is composed of lithics, pottery and human and faunistic remains. This paper presents ca. 700 yrs. BP radiocarbon dating and reports archaeofaunal and technological data. Lithic resources procurement, artifactual diversity and subsistence are discussed. It is proposed that the site was a residential base related to a spatially segregated burial. The site provides novel information on the mobility circuits in the southwest of Buenos Aires province in the Late Holocene.Facultad de Ciencias Naturales y Muse

Paso Vanoli: una instalación del Holoceno tardío en valles fluviales del sudoeste bonaerense

En este trabajo se presentan los estudios realizados sobre la colección arqueológica del sitio Paso Vanoli, conservada en el Dpto. de Humanidades de la UNS. Los trabajos de campo fueron llevados a cabo en la década de 1970 por la Lic. Pérez Amat. Paso Vanoli es un vado en el valle inferior del arroyo Napostá en el ejido urbano de Bahía Blanca (38º 40´S; 62º 13´O), provincia de Buenos Aires. Es un sitio en estratigrafía, emplazado sobre un médano, en la margen derecha del arroyo. La colección está integrada por artefactos líticos, cerámica, materiales faunísticos y restos óseos humanos. En este trabajo se presenta un fechado radiocarbónico de ca. 700 años AP y se informan los datos relacionados con las arqueofaunas y la tecnología. Se discute el abastecimiento de recursos líticos, la variabilidad artefactual y la subsistencia. Se propone que el sitio fue una base residencial vinculada con un sector de inhumaciones espacialmente segregado. Este sitio aporta información novedosa sobre los circuitos de movilidad en el sudoeste bonaerense durante el Holoceno tardío final.This paper presents the studies performed on an archaeological collection from Paso Vanoli site, housed at the Departamento Humanidades, UNS. Field works were carried out in the late 1970´s by Lic. Pérez Amat. Paso Vanoli is a ford in the lower Arroyo Napostá (Napostá Stream) in the area of urban common land of Bahía Blanca (38º 40´S; 62º 13´O), in Buenos Aires Province. It is a stratigraphic site located on a dune on the right bank of the stream. The collection is composed of lithics, pottery and human and faunistic remains. This paper presents ca. 700 yrs. BP radiocarbon dating and reports archaeofaunal and technological data. Lithic resources procurement, artifactual diversity and subsistence are discussed. It is proposed that the site was a residential base related to a spatially segregated burial. The site provides novel information on the mobility circuits in the southwest of Buenos Aires province in the Late Holocene.Facultad de Ciencias Naturales y Muse

On the flexural vibration of cylinders under axial loads:Numerical and experimental study

The flexural vibration of a homogeneous isotropic linearly elastic cylinder of any aspect ratio is analysed in this paper. Natural frequencies of a cylinder under uniformly distributed axial loads acting on its bases are calculated numerically by the Ritz method with terms of power series in the coordinate directions as approximating functions. The effect of axial loads on the flexural vibration cannot be described by applying infinitesimal strain theory, therefore, geometrically nonlinear strain–displacement relations with second-order terms are considered here. The natural frequencies of free–free, clamped–clamped, and sliding–sliding cylinders subjected to axial loads are calculated using the proposed three-dimensional Ritz approach and are compared with those obtained with the finite element method and the Bernoulli–Euler theory. Different experiments with cylinders axially compressed by a hydraulic press are carried out and the experimental results for the lowest flexural frequency are compared with the numerical results. An approach based on the Ritz formulation is proposed for the flexural vibration of a cylinder between the platens of the press with constraints varying with the intensity of the compression. The results show that for low compressions the cylinder behaves similarly to a sliding–sliding cylinder, whereas for high compressions the cylinder vibrates as a clamped–clamped one

Efectos del entrenamiento en la habilidad para repetir sprints (RSA) en arbitros de baloncesto

La mayor parte de los estudios en baloncesto se han centrado en el estudio de los jugadores existiendo pocos que se hayan centrado en el estudio de los árbitros de baloncesto. La habilidad para repetir sprints (RSA) es uno de los componentes claves en el rendimiento físico en baloncesto. Por ello, el objetivo de este estudio es analizar la RSA y los valores cineantropométricos en árbitros de baloncesto después de un periodo de entrenamientode 5 semanas. 24 árbitros fueron analizados, divididos en Grupo Control (GC) y Grupo Experimental (GE). Se les realizó una determinación cineantropométrica (Talla, Peso, % Graso y IMC) y un test de RSA de 7x20 m. en dos ocasiones, antes y después de estas semanas de entrenamiento (PRE y POST). Encontramos pequeñas diferencias en el peso en ambos gruposentre el PRE y POST así como diferencias en el % graso, donde ambos disminuyeron, 2.5% el GC y 5.29% el GE. Las mejoras en el RSA fueron evidentes, siendo 0.67% para el GC y 5.10% para el GE. En conclusión, después de un entrenamiento específico, las mejoras en RSA en árbitros de baloncesto claramente mejorarán su condición física así como sus valorescineantropométricos

Improvements in tribological and anticorrosion performance of porous Ti-6Al-4V via PEO coating

Producción CientíficaMedical implants manufactured using biomaterial Ti-6Al-4V exhibit some disadvantages. Its higher elastic modulus than that of natural bone can cause stress shielding problems. This can be avoided using Ti-6Al-4V with pores in the implant structure. However, poor corrosion and tribocorrosion behaviors are yielded because of the large area exposed to the medium. To mitigate both issues, coating technologies can be applied. The plasma electrolytic oxidation (PEO) process is a cost-effective process that has been used successfully in nonporous Ti alloys. In this study, two PEO coatings with different amounts of Ca/P are used. However, reports regarding their application in porous materials are scarce. The effects of PEO treatments on corrosion and tribocorrosion in Ti-6Al-4V powder metallurgy are analyzed herein. The porous materials provide an efficient surface for PEO coatings, as demonstrated via scanning electron microscopy (SEM) and atomic force microscopy (AFM), and the porosity of the substrates improved the adherence of the coatings. The corrosion resistance measured via electrochemical impedance spectroscopy confirmed the beneficial effect of the coatings, particularly for long exposure time. The lower roughness, small pore size, and more compact film observed in the PEO-Ca/P sample resulted in favorable tribological and corrosion properties.Ministerio de Educación y Ciencia (project RTI2018-097990-B-I00)Junta de Castilla y León (projects VA275P18 and VA044G19

Global environmental changes: setting priorities for Latin American coastal habitats.

The definitive version is available at www.blackwell-synergy.comThe Intergovernmental Panel for Climate Change (IPCC) reports that Global Environmental Changes (GEC) are occurring quicker than at any other time over the last 25 million years and impacting upon marine environments (Bellard et al., 2012). There is overwhelming evidence showing that GEC are affecting both the quality and quantity of the goods and services provided by a wide range of marine ecosystems. In order to discuss regional preparedness for global environmental changes, a workshop was held in Ilhabela, Brazil (22- 26 April 2012) entitled "Evaluating the Sensitivity of Central and South American Benthic Communities to Global Environmental Changes" that drew together scientists from ten Latin American and three European countries. © 2013 Blackwell Publishing Ltd