Symbiosis numerical - hydraulic models

Peer Reviewe

An analysis of nearshore profile and bar development under large scale erosive and accretive waves

This is an Accepted Manuscript of an article published by Taylor & Francis Group in Journal of Hydraulic Research on 2018, available online at: http://www.tandfonline.com/10.1080/00221686.2017.1315748Typical morphodynamic laboratory tests have been carried out at small scales and without sufficient coverage or resolution. These limitations, applying particularly to accretive tests, have obstructed reliable observations and restricted modelling capabilities. Here we present experiments with erosive/accretive waves acting on a large scale flume bed profile. The paper reports a set of high-quality hydro-morphodynamic data. The analysis is focused on net transport rates and how these patterns change between different accretive conditions. The measured velocity and acceleration skewness are presented and discussed, linking the net transport over the bar to the measured hydrodynamics and sediment concentrations. The resulting profile behaviour is discussed as a function of hydro-morphodynamic settings to facilitate comparisons with other datasets.Peer ReviewedPostprint (author's final draft

A ferrofluid-based sensor to measure bottom shear stresses under currents and waves

This is an Accepted Manuscript of an article published by Taylor & Francis Group in Journal of Hydraulic Research on 2018, available online at: http://www.tandfonline.com/10.1080/00221686.2017.1397779The measurement of the near-bottom flow characteristics is crucial to correctly understand coastal processes. To overcome some of the limits of present state-of-the-art measuring instruments, we propose a novel approach to measure bottom shear stress under currents and waves based on the exploitation of magneto-rheological fluids, named ferrofluids. In particular, the deformation of a magnetically controlled ferrofluid drop O(0.01 ml) is transformed by a conditioning circuit into an output voltage which is proportional to the bottom shear stress. Calibration curves are presented for both steady-current and regular wave conditions, over fixed and weakly mobile beds, showing that the behaviour of the proposed measuring system can be assumed linear. In the range of the investigated parameters, it is shown that the working range is comprised between 0.08 N m-2 and an upper limit which is a function of the controlling magnetic field and the flow type.Peer ReviewedPostprint (author's final draft

Comparison between nested grids and unstructured grids for a high-resolution wave forecasting system in the western Mediterranean sea

This is an Accepted Manuscript of an article published by Taylor & Francis Group in Journal of Operational Oceanography on 2017, available online at: http://www.tandfonline.com/10.1080/1755876X.2016.1260389Traditionally wave modelling uses a downscaling process by means of successive nested grids to obtain high-resolution wave fields near the coast. This supposes an uncertain error due to internal boundary conditions and a long computational time. Unstructured grids avoid multiple meshes and thus the problem of internal boundary conditions. In the present study high resolution wave simulations are analysed for a full year where high-resolution meteorological models were available in the Catalan coast. This coastal case presents sharp gradients in bathymetry and orography and therefore correspondingly sharp variations in the wind and wave fields. Simulations with SWAN v.4091A using a traditional nested sequence and a regional unstructured grid have been compared. Also a local unstructured grid nested in an operational forecast system is included in the analysis. The obtained simulations are compared to wave observations from buoys near the coast; almost no differences are found between the unstructured grids and the regular grids. Simultaneously, tests have been carried out in order to analyse the computational time required for each of the alternatives, showing a decrease to less than half the time when working with regional unstructured grids and maintaining the forecast accuracy and coastal resolution with respect to the downscaling system.Peer ReviewedPostprint (author's final draft

Evolución en planta/perfil de una playa. Métodos predictivos

[ES] La regeneración/alimentación artificial de una playa supone reproducir una costa sedimentaria que, al igual que las costas naturales, estará sometida a una serie de procesos evolutivos. Estos procesos se esquematizan mediante el estudio de los cambios en planta y perfil de la playa, los cuales son comunes tanto para costas naturales como artificiales. A lo largo de este trabajo se presentan una serie de herramientas para evaluar tales cambios y, por tanto, para estimar la durabilidad de las obras de regeneración o, al menos, las fases evolutivas por las que pasarán.Parte de este trabajo ha sido realizado gracias a la colaboración del Programa de Clima Marítimo (Ente Público de Puertos del Estado) a través del convenio Procesos Hidrodinámicos en Zona de Rompientes.Sánchez-Arcilla Conejo, A.; Jiménez, JA. (1995). Evolución en planta/perfil de una playa. Métodos predictivos. Ingeniería del Agua. 2(1 Extraordinario):119-132. https://doi.org/10.4995/ia.1995.2662SWORD11913221 ExtraordinarioBerenguer, J.M. y Enríquez, J. (1988). Design of pocket beaches. Proc. 21st Coastal Eng. Conf.,ASCE, 1411-1425.Bodge, K. (1992). Representing equilibrium beach profiles with an exponential expression. J. of Coastal Research. 8, 47-55.Bruun, P. (1953). Forms of equilibrium coasts with littoral drift.Tech. Rep. 3, University of California, Engineering Research Laboratory, Berkeley.Bruun, P. (1954). Coast erosion and the development of beach profiles. Beach Erosion Board, Techn. Memo. 44.CUR. (1988). Manual on Artificial Beach Nourishment.Rijkswaterstaat, The Netherlands, 195 pp y anejos.Dalrymple, R.A. (1992). Prediction of storm/normal beach profiles. J. of Waterway. Port. Coastal and Ocean Engineering. 118, 2, 193-200.Dalrymple, R.A. y Thompson, W. (1976). Study of equilibrium beach profiles. Proc. 15th Coastal Eng. Conf.. ASCE. 1277-1296.Dean, R.G. (1973). Heuristic models of sand transpon in the surf zone. Proc. of the Conf. on Engineering Dynamics in the surf zone. 208-214.Dean, R.G. (1977). Equilibrium beach profiles: US Atlantic and Gulf Coasts. Dept. of Civil Eng., Ocean Eng. Tech. Rep. 12, Univ. of Delaware.Dean, R.G. (1997). Equilibrium beach profiles: characteristics and applications. J. of Coastal Research. 7, 1, 53-84.Dean, R.G. y Maurmeyer, E.M. (1983). Models for beach profile response. En: Komar, P.D. (ed.), Handbook of Coastal Processes and Erosion.CRC Press, Boca Ratón, 151-166.Dean, R.G. y Yoo, C. 1993. Predictability of beach nouríshment perfomance. En: Stauble, D.K. y Kraus, N.C. (eds.), Beach Nourishment Engineering and Management Considerations.ASCE, 86-102.De Vriend, H.J.; Zyserman, J.; Nicholson, J.; Roelvink, J.A.; Pechón, P. y Southgate, H.N. (1994). Medium-term 2DH coastal área modelling. Coastal Engineering. 21. 193-224.Garau, C. (1979). Condicionantes de la estabilidad de playas. A nálisis de la función polar de los salientes. II Curso de Ingeniería Oceanogràfica y Portuaria. Santander.Hedegaard, I.B.; Roelvink, J.A.; Southgate, H.; Pechón, P.; Nicholson, J. y Hamm, L. (1992). Intercomparison of coastal profile models. Proc. 23rd Coastal Eng. Conf.. ASCE, 2108-2121.Horikawa, K. (1988) Nearshore Dynamics and Coastal Processes. University of Tokyo Press, Tokyo.Hoyle, J.W. y King, G.T. (7955). The orígin and stability of beaches. Proc. 6th Coastal Eng. Conf.. ASCE,'281-301.Hsu, J.R.C. y Evans, C. (1989). Parabolic hay shapes and applications. Proc. Institution of Civil Engineers. 87, 557-570.Inman, D.L.; Elwany, M.H.S. y Jenkins, S.A. (1993). Shoreríse and bar-berm profiles on ocean beaches. J. of Geophysical Research, 98. C10.18181 -18199.Jiménez, J.A. (1995). BEACH1L. Laboratori d'Enginyeria Marítima, Universitat Politécnica de Catalunya, Barcelona, 41 pp y anejos.Jiménez, J.A. y Sánchez-Arcilla, A. (1992). Simulación de cambios a corto plazo en la línea de costa. Revista de Obras Públicas. 3315, 41-51.Jiménez, J.A. y Sánchez-Arcilla, A. (1993). Influencia de la pendiente en la evolución del perfil de playa. II Jornadas Españolas de Ingeniería de Costas y Puertos. Gijón (en prensa).Jiménez, J.A.; Sánchez-Arcilla, A. y Stive, M.J.F. (1993). Discussion on Prediction of storm/normal beach profiles. J. of Waterway, Port, Coastal and Ocean Engineering, 119, 4, 466-468.Jiménez, J.A.; Valdemoro, H. y Sánchez-Arcilla, A. (1995). Discussion on A nalysis of bayed beaches in static equilibríum. J. of Waterway. Port. Coastal and Ocean Engineering.Mav/June (en prensa).Komar, P.D. (1976). Beach Processes and Sedimentation. Prentice-Hall. Englewood Cliffs, 429 pp.Komar, P.D. y McDougal, W.G. (1994). The analysis of exponential beach profiles. J. of Coastal Research. 10, 1, 59-69.Kraus, N.C. (1985). Prediction models of shoreline change. En: Horikawa, K. (ed.), Nearshore Dynamics and Coastal Processes. University of Tokyo Press, Tokyo, 321-366.Kriebel, D.L. y Dean, R.G. (7995). Convolution method for time-dependent beach-profile response. J. of Waterway. Port. Coastal and Ocean Engineering. 119, 2, 204-226.Kriebel, D.L.; Kraus, N.C. y Larson, M. (1991). Engineering methods for predicting beach profile response. Coastal Sediments' 91.ASCE, 557-571.Larson, M. (1955). Ouantification of beach profile change.Report 1008, Dept. of water Resources Eng., Lund University.Larson, M. (1991). Equilibríum beach profiles of a beach with varying grain size. Coastal Sediments'91. ASCE, 905-919.Larson, M.; Hanson, H. y Kraus, N.C. (1987). Analytical solutions of the one-line model of shoreline change. Tech. Rep. CERC-87-15.Le Blond, P.H. (1972). On the formation of spiral beaches. Proc. 13th Coastal Eng. Conf.. ASCE, 1331-1345.Negro, V. (1990). La variabilidad de los perfiles de playa. Perfiles de verano e invierno. Análisis histórico(1a parte). Revista de Obras Publicas. Marzo 1990, 23-29.Ozasa, H. y Brampton, A.H. (1980). Mathematical modelling of beaches backed by seawalls. Coastal Engineering. 4, 1, 47-64.Pelnard-Considere, R. (1956). Essai de theorie de l'evolution des formes de rivage de sable et de galets. 4th Journees de l'Hydraulique. Question III, Rapport 1, 289-298.Rivero, F. (1995). PROPS. Laboratori d'Enginyeria Marítima, Universitat Politécnica de Catalunya, Barcelona.Sánchez-Arcilla, A. y Jiménez, J.A. (1994). Ingeniería de playas (I): conceptos de morofología costera. Ingeniería del Agua. 1, 2, 97-114.Short, A.D. (ed.) (]993). Beach and surf zone morphodynamics. J. of Coastal Research.Special Issue 15.Silvester, R. (1970). Growth of crenulated shaped bays to equilibríum. J. of Waterways and Harbours División. 96, WW2, 275-287.Silvester, R. y Hsu, J.R.C. (1991). New and oíd ideas in coastal sedimentation. Reviews in Aquatic Sciences. 4, 4, 375-410.0Steetzel, H.J. (1993). Cross-shore transpon during storm surges.Ph.D. Thesis, Delft University of Technology, 242pp.Sunamura, T. (1984). Quantitativeprediction ofbeach-face slopes. Geological Soc. of Amer. Bull..95, 242-245.Sunamura, T. (1985). Beach morphologies and their change. En: Horikawa, K. (ed.), Nearshore Dynamics and Coastal Processes. Univ. of Tokyo Press, Tokyo, 136-157.Tan, S.K. y Chiew, Y.M. (1994). Analysis of bayed beaches in static equilibríum. J. of Waterway. Port. Coastal and Ocean Engineering. 120. 2, 145-153.Vellinga, P. (1982). Beach and dune erosión duríng storm. surges. Coastal Engineering, 6, 806-819.Vellinga, P. (1986). Beach and dune erosión during storm surges. Ph. D. Thesis, Delft University of Technology.Walton, T.L. (1994). Shoreline evolution for tapered beach fill. J. of Waterway. Port. Coastal and Ocean Engineering. 120, 6, 651-655. Wiegel, R.L. (1964) Oceanographic Engineering. Prentice-Hall, Englewood Cliffs.Wind, H.G. (1994). An analytical model of crenulate shaped beaches. Coastal Engineering. 23. 243-253.Yasso, W.E. (1965). Plan geometry of headland hay beaches. J. of Geology. 73. 702-714

REST-COAST, un projecte per salvar el Delta

Aquest projecte europeu, liderat pel Laboratori d’Enginyeria Marítima de la UPC i el Centre Internacional d’Investigació dels Recursos Costaners (CIIRC), té per objectiu desenvolupar una solució sistèmica per a la restauració costanera que es pugui replicar a gran escala i que les mesures aplicades s’incloguin en les polítiques nacionals i internacionals.Postprint (published version

Wave modelling in coastal and inner seas

In the long term development of the research on wind waves and their modelling, in particular of the inner and coastal seas, the present situation is framed with a short look at the past, a critical analysis of the present capabilities and a foresight of where the field is likely to go. After a short introduction, Chapter 2 deals with the basic processes at work and their modelling aspects. Chapter 3 highlights the interaction with wind and currents. Chapter 4 stresses the need for a more complete, spectral, approach in data assimilation. Chapter 5 summarizes the situation with a discussion on the present status in wave modelling and a look at what we can expect in the future.Peer ReviewedPostprint (author's final draft

Observing shoreline fluxes: implications for swash and surf zone modeling

The scarcity of reliable and controlled observations of water and sediment fluxes near the shore is one of the main reasons for the many remaining challenges in the field of morphodynamics. In this paper we shall present three largescale data sets from the CIEM flume of the Maritime Engineering Laboratory (LIM/UPC) in Barcelona, looking for the distinctive behaviour of such fluxes between erosive and accretive conditions. Two different erosive conditions are presented, which report an expected different behaviour of the bar and measured physical parameters (wave height, velocity and suspended sediment cocentration). These erosive time series also report an unexpected similitude on the profile comparisson between both data sets from the bar until the shoreline. The acquired data under accretive conditions present the important control played by the initial bar, controlling the hydrodynamics of the surf and swash zones.Postprint (published version

Analysis of current intensification in the NorthWest Mediterranean Shelf

Flow intensification episodes lasting more than 12 h are observed occasionally at different locations along the Northwestern Mediterranean coast. In the last years, these pulses have hindered ship operations outside the Barcelona harbour, thus attracting the attention of the port authorities. In this paper, the strongest intensification events in the Barcelona coast area are quantified and characterized in order to identify the mechanisms which generate them. For this, current, sea level and meteorological measured and modelled data, at local and regional scale, are analysed. The results show that the flow accelerations are due to the combination of a narrow coastal shelf and the prevalence of a strong and sustained wind from the NE to SE. The synoptic atmospheric conditions that lead to this meteorological scenario are described. For one of the events, the presence and contribution to the current fluctuations of a coastal trapped wave, likely generated at the Eastern edge of the Gulf of Lions shelf, and other factors such as a freshwater discharge are also identified and discussed.Peer ReviewedPostprint (author's final draft

Experimental set-up and calibration errors for mapping wave-breaking pressures on marine structures

Capturing the detailed spatial variation of pressures induced by breaking waves on physical model structures has become possible using a high resolution mapping system. It can provide data with 4 measuring points/cm2, whereas the denser pressure measurements reported so far, for wave-structure interaction experiments, were limited to 0.4 pressure transducers/cm2. The paper explores the main parameters affecting the accuracy and errors of pressure data induced by laboratory set-up and system calibration. The quality of pressure maps deteriorates due to cushioning effects associated to air trapped in the sensor during manufacturing. The sensor's response is also shown to depend on the loading conditions. Non-calibrated outputs returned for impact pressures induced by impinging water-jets are more than three times smaller than the outputs recorded for static pressures, and/or for pressures developed when a material less compliant than water comes forcibly in contact with the sensor. Therefore, the calibration settings must be similar to the conditions anticipated in the experiments. To this end, a set-up and calibration methodology, designed specifically for hydraulic model tests with waves breaking on structures, are proposed and discussed in the paper.Peer ReviewedPostprint (author's final draft