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119 results on '"Branger H"'

1. Separatrix crossing and symmetry breaking in NLSE-like systems due to forcing and damping

Author

Eeltink, D., Armaroli, A., Luneau, C., Brunetti, M., Branger, H., and Kasparian, J.

Subjects
Nonlinear Sciences - Pattern Formation and Solitons, Nonlinear Sciences - Chaotic Dynamics, Physics - Fluid Dynamics
Abstract

We theoretically and experimentally examine the effect of forcing and damping on systems that can be described by the nonlinear Schr\"odinger equation (NLSE), by making use of the phase-space predictions of the three-wave truncation of the spectrum. In the latter, only the fundamental frequency and the upper and lower sidebands are retained. Plane wave solutions to the NLSE exhibit modulation instability (MI) within a frequency band determined by a linear stability analysis. For modulation frequencies inside the MI-band, we experimentally demonstrate that forcing and damping cause a separatrix crossing during the evolution. Our experiments are performed on deep water waves, which are better described by the higher-order NLSE, the Dysthe equation. We therefore extend our analysis to this system. However, our conclusions are general. When the system is damped by the viscosity of the water, it is pulled outside the separatrix, which in the real space corresponds to a phase-shift of the envelope and therefore doubles the period of the Fermi-Pasta-Ulam-Tsingou recurrence cycle. When the system is forced by the wind, it is pulled inside the separatrix. Furthermore, for modulation frequencies outside the conventional MI-band, we experimentally demonstrate that contrary to the linear prediction, we do observe a growth and decay cycle of the plane-wave modulation. Finally, we give a theoretical demonstration that forcing the NLSE system can induce symmetry breaking during the evolution., Comment: 12 pages, 9 figures

Published
2020

2. Spectral up- and downshifting of Akhmediev breathers under wind forcing

Author

Eeltink, D., Lemoine, A., Branger, H., Kimmoun, O., Kharif, C., Carter, J., Chabchoub, A., Brunetti, M., and Kasparian, J.

Subjects
Physics - Fluid Dynamics
Abstract

We experimentally and numerically investigate the effect of wind forcing on the spectral dynamics of Akhmediev breathers, a wave-type known to model the modulation instability. We develop the wind model to the same order in steepness as the higher order modifcation of the nonlinear Schroedinger equation, also referred to as the Dysthe equation. This results in an asymmetric wind term in the higher order, in addition to the leading order wind forcing term. The derived model is in good agreement with laboratory experiments within the range of the facility's length. We show that the leading order forcing term amplifies all frequencies equally and therefore induces only a broadening of the spectrum while the asymmetric higher order term in the model enhances higher frequencies more than lower ones. Thus, the latter term induces a permanent upshift of the spectral mean. On the other hand, in contrast to the direct effect of wind forcing, wind can indirectly lead to frequency downshifts, due to dissipative effects such as wave breaking, or through amplification of the intrinsic spectral asymmetry of the Dysthe equation. Furthermore, the definitions of the up- and downshift in terms of peak- and mean frequencies, that are critical to relate our work to previous results, are highlighted and discussed., Comment: 30 pages, 11 figures

Published
2017
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4. Modulation Instability and Phase-Shifted Fermi-Pasta-Ulam Recurrence

Author

Kimmoun, O., Hsu, H. C., Branger, H., Li, M. S., Chen, Y. Y., Kharif, C., Onorato, M., Kelleher, E. J. R., Kibler, B., Akhmediev, N., and Chabchoub, A.

Subjects
Nonlinear Sciences - Pattern Formation and Solitons, Physics - Fluid Dynamics
Abstract

Instabilities are common phenomena frequently observed in nature, sometimes leading to unexpected catastrophes and disasters in seemingly normal conditions. The simplest form of instability in a distributed system is its response to a harmonic modulation. Such instability has special names in various branches of physics and is generally known as modulation instability (MI). The MI is tightly related to Fermi-Pasta-Ulam (FPU) recurrence since breather solutions of the nonlinear Schr\"odinger equation (NLSE) are known to accurately describe growth and decay of modulationally unstable waves in conservative systems. Here, we report theoretical, numerical and experimental evidence of the effect of dissipation on FPU cycles in a super wave tank, namely their shift in a determined order. In showing that ideal NLSE breather solutions can describe such dissipative nonlinear dynamics, our results may impact the interpretation of a wide range of new physics scenarios., Comment: 6 pages, 7 figures

Published
2016

5. Nonlinear wave evolution with data-driven breaking

Author

Eeltink, D., Branger, H., Luneau, C., He, Y., Chabchoub, A., Kasparian, J., van den Bremer, T. S., Sapsis, T. P., Eeltink, D., Branger, H., Luneau, C., He, Y., Chabchoub, A., Kasparian, J., van den Bremer, T. S., and Sapsis, T. P.

Abstract

Wave breaking is the main mechanism that dissipates energy input into ocean waves by wind and transferred across the spectrum by nonlinearity. It determines the properties of a sea state and plays a crucial role in ocean-atmosphere interaction, ocean pollution, and rogue waves. Owing to its turbulent nature, wave breaking remains too computationally demanding to solve using direct numerical simulations except in simple, short-duration circumstances. To overcome this challenge, we present a blended machine learning framework in which a physics-based nonlinear evolution model for deep-water, non-breaking waves and a recurrent neural network are combined to predict the evolution of breaking waves. We use wave tank measurements rather than simulations to provide training data and use a long short-term memory neural network to apply a finite-domain correction to the evolution model. Our blended machine learning framework gives excellent predictions of breaking and its effects on wave evolution, including for external data.

Published
2024

6. Experiments on wind-perturbed rogue wave hydrodynamics using the Peregrine breather model

Author

Chabchoub, A., Hoffmann, N., Branger, H., Kharif, C., and Akhmediev, N.

Subjects
Physics - Fluid Dynamics
Abstract

Being considered as a prototype for description of oceanic rogue waves (RWs), the Peregrine breather solution of the nonlinear Schr\"odinger equation (NLS) has been recently observed and intensely investigated experimentally in particular within the context of water waves. Here, we report the experimental results showing the evolution of the Peregrine solution in the presence of wind forcing in the direction of wave propagation. The results show the persistence of the breather evolution dynamics even in the presence of strong wind and chaotic wave field generated by it. Furthermore, we have shown that characteristic spectrum of the Peregrine breather persists even at the highest values of the generated wind velocities thus making it a viable characteristic for prediction of rogue waves., Comment: The Journal submission policies dot not allowing any previous submissions!

Published
2013
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7. The growth of wind-waves in finite depth

Author

Montalvo, P., Dorignac, J., Manna, M. A., Kharif, C., and Branger, H.

Subjects
Physics - Fluid Dynamics
Abstract

In order to study the growth of wind waves in finite depth we extend Miles' theory to the finite depth domain. A depth-dependent wave growth rate is derived from the dispersion relation of the wind/water interface. A suitable dimensionless finite depth wave age parameter allows us to plot a family of wave growth curves, each family member characterized by the water depth. Two major results are that for small wave age, the wave growth rates are comparable to those of deep water and for large wave age, a finite-depth wave-age-limited growth is reached, with wave growth rates going to zero. The corresponding limiting wave length and limiting phase speed are explicitely calculated in the shallow and in the deep water cases. A qualitative agreement with well-known empirical results is established and shows the robust consistency of the linear theoretical approach., Comment: 10 pages, 3 figures, submitted to the Journal of Fluid Mechanics

Published
2012

9. EUREC4A

Author

Stevens, B, Bony, S, Farrell, D, Ament, F, Blyth, A, Fairall, C, Karstensen, J, Quinn, P, Speich, S, Acquistapace, C, Aemisegger, F, Albright, A, Bellenger, H, Bodenschatz, E, Caesar, K, Chewitt-Lucas, R, De Boer, G, Delanoe, J, Denby, L, Ewald, F, Fildier, B, Forde, M, George, G, Gross, S, Hagen, M, Hausold, A, Heywood, K, Hirsch, L, Jacob, M, Jansen, F, Kinne, S, Klocke, D, Kolling, T, Konow, H, Lothon, M, Mohr, W, Naumann, A, Nuijens, L, Olivier, L, Pincus, R, Pohlker, M, Reverdin, G, Roberts, G, Schnitt, S, Schulz, H, Pier Siebesma, A, Stephan, C, Sullivan, P, Touze-Peiffer, L, Vial, J, Vogel, R, Zuidema, P, Alexander, N, Alves, L, Arixi, S, Asmath, H, Bagheri, G, Baier, K, Bailey, A, Baranowski, D, Baron, A, Barrau, S, Barrett, P, Batier, F, Behrendt, A, Bendinger, A, Beucher, F, Bigorre, S, Blades, E, Blossey, P, Bock, O, Boing, S, Bosser, P, Bourras, D, Bouruet-Aubertot, P, Bower, K, Branellec, P, Branger, H, Brennek, M, Brewer, A, Brilouet, P, Brugmann, B, Buehler, S, Burke, E, Burton, R, Calmer, R, Canonici, J, Carton, X, Cato, G, Charles, J, Chazette, P, Chen, Y, Chilinski, M, Choularton, T, Chuang, P, Clarke, S, Coe, H, Cornet, C, Coutris, P, Couvreux, F, Crewell, S, Cronin, T, Cui, Z, Cuypers, Y, Daley, A, Damerell, G, Dauhut, T, Deneke, H, Desbios, J, Dorner, S, Donner, S, Douet, V, Drushka, K, Dutsch, M, Ehrlich, A, Emanuel, K, Emmanouilidis, A, Etienne, J, Etienne-Leblanc, S, Faure, G, Feingold, G, Ferrero, L, Fix, A, Flamant, C, Flatau, P, Foltz, G, Forster, L, Furtuna, I, Gadian, A, Galewsky, J, Gallagher, M, Gallimore, P, Gaston, C, Gentemann, C, Geyskens, N, Giez, A, Gollop, J, Gouirand, I, Gourbeyre, C, De Graaf, D, De Groot, G, Grosz, R, Guttler, J, Gutleben, M, Hall, K, Harris, G, Helfer, K, Henze, D, Herbert, C, Holanda, B, Ibanez-Landeta, A, Intrieri, J, Iyer, S, Julien, F, Kalesse, H, Kazil, J, Kellman, A, Kidane, A, Kirchner, U, Klingebiel, M, Korner, M, Kremper, L, Kretzschmar, J, Kruger, O, Kumala, W, Kurz, A, L'Hegaret, P, Labaste, M, Lachlan-Cope, T, Laing, A, Landschutzer, P, Lang, T, Lange, D, Lange, I, Laplace, C, Lavik, G, Laxenaire, R, Lebihan, C, Leandro, M, Lefevre, N, Lena, M, Lenschow, D, Li, Q, Lloyd, G, Los, S, Losi, N, Lovell, O, Luneau, C, Makuch, P, Malinowski, S, Manta, G, Marinou, E, Marsden, N, Masson, S, Maury, N, Mayer, B, Mayers-Als, M, Mazel, C, Mcgeary, W, Mcwilliams, J, Mech, M, Mehlmann, M, Meroni, A, Mieslinger, T, Minikin, A, Minnett, P, Moller, G, Avalos, Y, Muller, C, Musat, I, Napoli, A, Neuberger, A, Noisel, C, Noone, D, Nordsiek, F, Nowak, J, Oswald, L, Parker, D, Peck, C, Person, R, Philippi, M, Plueddemann, A, Pohlker, C, Portge, V, Poschl, U, Pologne, L, Posyniak, M, Prange, M, Melendez, E, Radtke, J, Ramage, K, Reimann, J, Renault, L, Reus, K, Reyes, A, Ribbe, J, Ringel, M, Ritschel, M, Rocha, C, Rochetin, N, Rottenbacher, J, Rollo, C, Royer, H, Sadoulet, P, Saffin, L, Sandiford, S, Sandu, I, Schafer, M, Schemann, V, Schirmacher, I, Schlenczek, O, Schmidt, J, Schroder, M, Schwarzenboeck, A, Sealy, A, Senff, C, Serikov, I, Shohan, S, Siddle, E, Smirnov, A, Spath, F, Spooner, B, Katharina Stolla, M, Szkolka, W, De Szoeke, S, Tarot, S, Tetoni, E, Thompson, E, Thomson, J, Tomassini, L, Totems, J, Ubele, A, Villiger, L, Von Arx, J, Wagner, T, Walther, A, Webber, B, Wendisch, M, Whitehall, S, Wiltshire, A, Wing, A, Wirth, M, Wiskandt, J, Wolf, K, Worbes, L, Wright, E, Wulfmeyer, V, Young, S, Zhang, C, Zhang, D, Ziemen, F, Zinner, T, Zoger, M, Stevens B., Bony S., Farrell D., Ament F., Blyth A., Fairall C., Karstensen J., Quinn P. K., Speich S., Acquistapace C., Aemisegger F., Albright A. L., Bellenger H., Bodenschatz E., Caesar K. -A., Chewitt-Lucas R., De Boer G., Delanoe J., Denby L., Ewald F., Fildier B., Forde M., George G., Gross S., Hagen M., Hausold A., Heywood K. J., Hirsch L., Jacob M., Jansen F., Kinne S., Klocke D., Kolling T., Konow H., Lothon M., Mohr W., Naumann A. K., Nuijens L., Olivier L., Pincus R., Pohlker M., Reverdin G., Roberts G., Schnitt S., Schulz H., Pier Siebesma A., Stephan C. C., Sullivan P., Touze-Peiffer L., Vial J., Vogel R., Zuidema P., Alexander N., Alves L., Arixi S., Asmath H., Bagheri G., Baier K., Bailey A., Baranowski D., Baron A., Barrau S., Barrett P. A., Batier F., Behrendt A., Bendinger A., Beucher F., Bigorre S., Blades E., Blossey P., Bock O., Boing S., Bosser P., Bourras D., Bouruet-Aubertot P., Bower K., Branellec P., Branger H., Brennek M., Brewer A., Brilouet P. -E., Brugmann B., Buehler S. A., Burke E., Burton R., Calmer R., Canonici J. -C., Carton X., Cato G., Charles J. A., Chazette P., Chen Y., Chilinski M. T., Choularton T., Chuang P., Clarke S., Coe H., Cornet C., Coutris P., Couvreux F., Crewell S., Cronin T., Cui Z., Cuypers Y., Daley A., Damerell G. M., Dauhut T., Deneke H., Desbios J. -P., Dorner S., Donner S., Douet V., Drushka K., Dutsch M., Ehrlich A., Emanuel K., Emmanouilidis A., Etienne J. -C., Etienne-Leblanc S., Faure G., Feingold G., Ferrero L., Fix A., Flamant C., Flatau P. J., Foltz G. R., Forster L., Furtuna I., Gadian A., Galewsky J., Gallagher M., Gallimore P., Gaston C., Gentemann C., Geyskens N., Giez A., Gollop J., Gouirand I., Gourbeyre C., De Graaf D., De Groot G. E., Grosz R., Guttler J., Gutleben M., Hall K., Harris G., Helfer K. C., Henze D., Herbert C., Holanda B., Ibanez-Landeta A., Intrieri J., Iyer S., Julien F., Kalesse H., Kazil J., Kellman A., Kidane A. T., Kirchner U., Klingebiel M., Korner M., Kremper L. A., Kretzschmar J., Kruger O., Kumala W., Kurz A., L'Hegaret P., Labaste M., Lachlan-Cope T., Laing A., Landschutzer P., Lang T., Lange D., Lange I., Laplace C., Lavik G., Laxenaire R., LeBihan C., Leandro M., Lefevre N., Lena M., Lenschow D., Li Q., Lloyd G., Los S., Losi N., Lovell O., Luneau C., Makuch P., Malinowski S., Manta G., Marinou E., Marsden N., Masson S., Maury N., Mayer B., Mayers-Als M., Mazel C., McGeary W., McWilliams J. C., Mech M., Mehlmann M., Meroni A. N., Mieslinger T., Minikin A., Minnett P., Moller G., Avalos Y. M., Muller C., Musat I., Napoli A., Neuberger A., Noisel C., Noone D., Nordsiek F., Nowak J. L., Oswald L., Parker D. J., Peck C., Person R., Philippi M., Plueddemann A., Pohlker C., Portge V., Poschl U., Pologne L., Posyniak M., Prange M., Melendez E. Q., Radtke J., Ramage K., Reimann J., Renault L., Reus K., Reyes A., Ribbe J., Ringel M., Ritschel M., Rocha C. B., Rochetin N., Rottenbacher J., Rollo C., Royer H., Sadoulet P., Saffin L., Sandiford S., Sandu I., Schafer M., Schemann V., Schirmacher I., Schlenczek O., Schmidt J., Schroder M., Schwarzenboeck A., Sealy A., Senff C. J., Serikov I., Shohan S., Siddle E., Smirnov A., Spath F., Spooner B., Katharina Stolla M., Szkolka W., De Szoeke S. P., Tarot S., Tetoni E., Thompson E., Thomson J., Tomassini L., Totems J., Ubele A. A., Villiger L., Von Arx J., Wagner T., Walther A., Webber B., Wendisch M., Whitehall S., Wiltshire A., Wing A. A., Wirth M., Wiskandt J., Wolf K., Worbes L., Wright E., Wulfmeyer V., Young S., Zhang C., Zhang D., Ziemen F., Zinner T., Zoger M., Stevens, B, Bony, S, Farrell, D, Ament, F, Blyth, A, Fairall, C, Karstensen, J, Quinn, P, Speich, S, Acquistapace, C, Aemisegger, F, Albright, A, Bellenger, H, Bodenschatz, E, Caesar, K, Chewitt-Lucas, R, De Boer, G, Delanoe, J, Denby, L, Ewald, F, Fildier, B, Forde, M, George, G, Gross, S, Hagen, M, Hausold, A, Heywood, K, Hirsch, L, Jacob, M, Jansen, F, Kinne, S, Klocke, D, Kolling, T, Konow, H, Lothon, M, Mohr, W, Naumann, A, Nuijens, L, Olivier, L, Pincus, R, Pohlker, M, Reverdin, G, Roberts, G, Schnitt, S, Schulz, H, Pier Siebesma, A, Stephan, C, Sullivan, P, Touze-Peiffer, L, Vial, J, Vogel, R, Zuidema, P, Alexander, N, Alves, L, Arixi, S, Asmath, H, Bagheri, G, Baier, K, Bailey, A, Baranowski, D, Baron, A, Barrau, S, Barrett, P, Batier, F, Behrendt, A, Bendinger, A, Beucher, F, Bigorre, S, Blades, E, Blossey, P, Bock, O, Boing, S, Bosser, P, Bourras, D, Bouruet-Aubertot, P, Bower, K, Branellec, P, Branger, H, Brennek, M, Brewer, A, Brilouet, P, Brugmann, B, Buehler, S, Burke, E, Burton, R, Calmer, R, Canonici, J, Carton, X, Cato, G, Charles, J, Chazette, P, Chen, Y, Chilinski, M, Choularton, T, Chuang, P, Clarke, S, Coe, H, Cornet, C, Coutris, P, Couvreux, F, Crewell, S, Cronin, T, Cui, Z, Cuypers, Y, Daley, A, Damerell, G, Dauhut, T, Deneke, H, Desbios, J, Dorner, S, Donner, S, Douet, V, Drushka, K, Dutsch, M, Ehrlich, A, Emanuel, K, Emmanouilidis, A, Etienne, J, Etienne-Leblanc, S, Faure, G, Feingold, G, Ferrero, L, Fix, A, Flamant, C, Flatau, P, Foltz, G, Forster, L, Furtuna, I, Gadian, A, Galewsky, J, Gallagher, M, Gallimore, P, Gaston, C, Gentemann, C, Geyskens, N, Giez, A, Gollop, J, Gouirand, I, Gourbeyre, C, De Graaf, D, De Groot, G, Grosz, R, Guttler, J, Gutleben, M, Hall, K, Harris, G, Helfer, K, Henze, D, Herbert, C, Holanda, B, Ibanez-Landeta, A, Intrieri, J, Iyer, S, Julien, F, Kalesse, H, Kazil, J, Kellman, A, Kidane, A, Kirchner, U, Klingebiel, M, Korner, M, Kremper, L, Kretzschmar, J, Kruger, O, Kumala, W, Kurz, A, L'Hegaret, P, Labaste, M, Lachlan-Cope, T, Laing, A, Landschutzer, P, Lang, T, Lange, D, Lange, I, Laplace, C, Lavik, G, Laxenaire, R, Lebihan, C, Leandro, M, Lefevre, N, Lena, M, Lenschow, D, Li, Q, Lloyd, G, Los, S, Losi, N, Lovell, O, Luneau, C, Makuch, P, Malinowski, S, Manta, G, Marinou, E, Marsden, N, Masson, S, Maury, N, Mayer, B, Mayers-Als, M, Mazel, C, Mcgeary, W, Mcwilliams, J, Mech, M, Mehlmann, M, Meroni, A, Mieslinger, T, Minikin, A, Minnett, P, Moller, G, Avalos, Y, Muller, C, Musat, I, Napoli, A, Neuberger, A, Noisel, C, Noone, D, Nordsiek, F, Nowak, J, Oswald, L, Parker, D, Peck, C, Person, R, Philippi, M, Plueddemann, A, Pohlker, C, Portge, V, Poschl, U, Pologne, L, Posyniak, M, Prange, M, Melendez, E, Radtke, J, Ramage, K, Reimann, J, Renault, L, Reus, K, Reyes, A, Ribbe, J, Ringel, M, Ritschel, M, Rocha, C, Rochetin, N, Rottenbacher, J, Rollo, C, Royer, H, Sadoulet, P, Saffin, L, Sandiford, S, Sandu, I, Schafer, M, Schemann, V, Schirmacher, I, Schlenczek, O, Schmidt, J, Schroder, M, Schwarzenboeck, A, Sealy, A, Senff, C, Serikov, I, Shohan, S, Siddle, E, Smirnov, A, Spath, F, Spooner, B, Katharina Stolla, M, Szkolka, W, De Szoeke, S, Tarot, S, Tetoni, E, Thompson, E, Thomson, J, Tomassini, L, Totems, J, Ubele, A, Villiger, L, Von Arx, J, Wagner, T, Walther, A, Webber, B, Wendisch, M, Whitehall, S, Wiltshire, A, Wing, A, Wirth, M, Wiskandt, J, Wolf, K, Worbes, L, Wright, E, Wulfmeyer, V, Young, S, Zhang, C, Zhang, D, Ziemen, F, Zinner, T, Zoger, M, Stevens B., Bony S., Farrell D., Ament F., Blyth A., Fairall C., Karstensen J., Quinn P. K., Speich S., Acquistapace C., Aemisegger F., Albright A. L., Bellenger H., Bodenschatz E., Caesar K. -A., Chewitt-Lucas R., De Boer G., Delanoe J., Denby L., Ewald F., Fildier B., Forde M., George G., Gross S., Hagen M., Hausold A., Heywood K. J., Hirsch L., Jacob M., Jansen F., Kinne S., Klocke D., Kolling T., Konow H., Lothon M., Mohr W., Naumann A. K., Nuijens L., Olivier L., Pincus R., Pohlker M., Reverdin G., Roberts G., Schnitt S., Schulz H., Pier Siebesma A., Stephan C. C., Sullivan P., Touze-Peiffer L., Vial J., Vogel R., Zuidema P., Alexander N., Alves L., Arixi S., Asmath H., Bagheri G., Baier K., Bailey A., Baranowski D., Baron A., Barrau S., Barrett P. A., Batier F., Behrendt A., Bendinger A., Beucher F., Bigorre S., Blades E., Blossey P., Bock O., Boing S., Bosser P., Bourras D., Bouruet-Aubertot P., Bower K., Branellec P., Branger H., Brennek M., Brewer A., Brilouet P. -E., Brugmann B., Buehler S. A., Burke E., Burton R., Calmer R., Canonici J. -C., Carton X., Cato G., Charles J. A., Chazette P., Chen Y., Chilinski M. T., Choularton T., Chuang P., Clarke S., Coe H., Cornet C., Coutris P., Couvreux F., Crewell S., Cronin T., Cui Z., Cuypers Y., Daley A., Damerell G. M., Dauhut T., Deneke H., Desbios J. -P., Dorner S., Donner S., Douet V., Drushka K., Dutsch M., Ehrlich A., Emanuel K., Emmanouilidis A., Etienne J. -C., Etienne-Leblanc S., Faure G., Feingold G., Ferrero L., Fix A., Flamant C., Flatau P. J., Foltz G. R., Forster L., Furtuna I., Gadian A., Galewsky J., Gallagher M., Gallimore P., Gaston C., Gentemann C., Geyskens N., Giez A., Gollop J., Gouirand I., Gourbeyre C., De Graaf D., De Groot G. E., Grosz R., Guttler J., Gutleben M., Hall K., Harris G., Helfer K. C., Henze D., Herbert C., Holanda B., Ibanez-Landeta A., Intrieri J., Iyer S., Julien F., Kalesse H., Kazil J., Kellman A., Kidane A. T., Kirchner U., Klingebiel M., Korner M., Kremper L. A., Kretzschmar J., Kruger O., Kumala W., Kurz A., L'Hegaret P., Labaste M., Lachlan-Cope T., Laing A., Landschutzer P., Lang T., Lange D., Lange I., Laplace C., Lavik G., Laxenaire R., LeBihan C., Leandro M., Lefevre N., Lena M., Lenschow D., Li Q., Lloyd G., Los S., Losi N., Lovell O., Luneau C., Makuch P., Malinowski S., Manta G., Marinou E., Marsden N., Masson S., Maury N., Mayer B., Mayers-Als M., Mazel C., McGeary W., McWilliams J. C., Mech M., Mehlmann M., Meroni A. N., Mieslinger T., Minikin A., Minnett P., Moller G., Avalos Y. M., Muller C., Musat I., Napoli A., Neuberger A., Noisel C., Noone D., Nordsiek F., Nowak J. L., Oswald L., Parker D. J., Peck C., Person R., Philippi M., Plueddemann A., Pohlker C., Portge V., Poschl U., Pologne L., Posyniak M., Prange M., Melendez E. Q., Radtke J., Ramage K., Reimann J., Renault L., Reus K., Reyes A., Ribbe J., Ringel M., Ritschel M., Rocha C. B., Rochetin N., Rottenbacher J., Rollo C., Royer H., Sadoulet P., Saffin L., Sandiford S., Sandu I., Schafer M., Schemann V., Schirmacher I., Schlenczek O., Schmidt J., Schroder M., Schwarzenboeck A., Sealy A., Senff C. J., Serikov I., Shohan S., Siddle E., Smirnov A., Spath F., Spooner B., Katharina Stolla M., Szkolka W., De Szoeke S. P., Tarot S., Tetoni E., Thompson E., Thomson J., Tomassini L., Totems J., Ubele A. A., Villiger L., Von Arx J., Wagner T., Walther A., Webber B., Wendisch M., Whitehall S., Wiltshire A., Wing A. A., Wirth M., Wiskandt J., Wolf K., Worbes L., Wright E., Wulfmeyer V., Young S., Zhang C., Zhang D., Ziemen F., Zinner T., and Zoger M.

Abstract

The science guiding the EUREC4A campaign and its measurements is presented. EUREC4A comprised roughly 5 weeks of measurements in the downstream winter trades of the North Atlantic - eastward and southeastward of Barbados. Through its ability to characterize processes operating across a wide range of scales, EUREC4A marked a turning point in our ability to observationally study factors influencing clouds in the trades, how they will respond to warming, and their link to other components of the earth system, such as upper-ocean processes or the life cycle of particulate matter. This characterization was made possible by thousands (2500) of sondes distributed to measure circulations on meso- (200 km) and larger (500 km) scales, roughly 400 h of flight time by four heavily instrumented research aircraft; four global-class research vessels; an advanced ground-based cloud observatory; scores of autonomous observing platforms operating in the upper ocean (nearly 10 000 profiles), lower atmosphere (continuous profiling), and along the air-sea interface; a network of water stable isotopologue measurements; targeted tasking of satellite remote sensing; and modeling with a new generation of weather and climate models. In addition to providing an outline of the novel measurements and their composition into a unified and coordinated campaign, the six distinct scientific facets that EUREC4A explored - from North Brazil Current rings to turbulence-induced clustering of cloud droplets and its influence on warm-rain formation - are presented along with an overview of EUREC4A's outreach activities, environmental impact, and guidelines for scientific practice. Track data for all platforms are standardized and accessible at 10.25326/165 , and a film documenting the campaign is provided as a video supplement.

Published
2021

12. Nonlinear wave evolution with data-driven breaking

Author

Eeltink, D. (author), Branger, H. (author), Luneau, C. (author), He, Y. (author), Chabchoub, A. (author), Kasparian, J. (author), van den Bremer, T.S. (author), Sapsis, T. P. (author), Eeltink, D. (author), Branger, H. (author), Luneau, C. (author), He, Y. (author), Chabchoub, A. (author), Kasparian, J. (author), van den Bremer, T.S. (author), and Sapsis, T. P. (author)

Abstract

Wave breaking is the main mechanism that dissipates energy input into ocean waves by wind and transferred across the spectrum by nonlinearity. It determines the properties of a sea state and plays a crucial role in ocean-atmosphere interaction, ocean pollution, and rogue waves. Owing to its turbulent nature, wave breaking remains too computationally demanding to solve using direct numerical simulations except in simple, short-duration circumstances. To overcome this challenge, we present a blended machine learning framework in which a physics-based nonlinear evolution model for deep-water, non-breaking waves and a recurrent neural network are combined to predict the evolution of breaking waves. We use wave tank measurements rather than simulations to provide training data and use a long short-term memory neural network to apply a finite-domain correction to the evolution model. Our blended machine learning framework gives excellent predictions of breaking and its effects on wave evolution, including for external data., Environmental Fluid Mechanics

Published
2022
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13. Formation and evolution of a freshwater plume in the northwestern tropical Atlantic in February 2020

Author

Reverdin, G., Olivier, L., Foltz, G. R., Speich, S., Karstensen, J., Horstmann, J., Zhang, D., Laxenaire, R., Carton, Xavier, Branger, H., Carrasco, R., Boutin, J., Reverdin, G., Olivier, L., Foltz, G. R., Speich, S., Karstensen, J., Horstmann, J., Zhang, D., Laxenaire, R., Carton, Xavier, Branger, H., Carrasco, R., and Boutin, J.

Abstract

In February 2020, a 120km‐wide freshwater plume was documented by satellite and in situ observations near the Demerara Rise (7°N/54‐56°W). It was initially stratified in the upper 10 m with a freshwater content of 2 to 3 meters of Amazon water distributed down to 40 m. On February 2nd, ship transects indicate an inhomogeneous shelf structure with a propagating front in its midst, whereas minimum salinity close to 30 pss was observed close to the shelf break on February 5th. The salinity minimum eroded in time but was still observed 13 to 16 days later with 33.3 pss minimum value up to 400 km from the shelf break. At this time, the mixed layer depth was close to 20 m. The off‐shelf flow lasted 10 days, contributing to a plume area extending over 100000 km2 and associated with a 0.15 106 m3 s‐1 freshwater transport. The off‐shelf plume was steered northward by a North Brazil Current ring up to 12°N and then extended westward toward the Caribbean Sea. Its occurrence followed 3 days of favourable wind direction closer to the Amazon estuary, which contributed to north‐westward freshwater transport on the shelf. Other such events of freshwater transport in January‐March are documented since 2010 in salinity satellite products in 7 out of 10 years, and in 6 of those years, they were preceded by a change in wind direction between the Amazon estuary and the Guianas favouring the north‐westward freshwater transport toward the shelf break. Plain Language Summary This paper documents how freshwater from the Amazon reaches the deep ocean up to 12°N in the northwest tropical Atlantic in January‐March. The classical view is that the water is channelled along the shelf to the Caribbean Sea. Here, we document a freshwater plume from in situ and satellite observations during the EUREC4A‐OA/ATOMIC program in 2020. This plume separated from the shelf near 55°W north of French Guiana on February 2‐5. This fresher water was stirred by a North Brazil Current ring up to 12°N before mostly

Published
2021
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15. Time-frequency application with the stokes-woodward technique

Author

Elfouhaily, T., Guignard, S., Branger, H., Thompson, D.R., Chapron, B., and Vandemark, D.

Subjects
Remote sensing -- Research, Business, Earth sciences, Electronics and electrical industries
Abstract

In a recent paper, we have generalized Woodward's theorem and applied it to the case of random signals jointly modulated in amplitude and frequency. This generalization yields a new spectral technique to estimate the amount of energy due to mode coupling without calling for higher order statistics. Two power spectra are detected; the first is related to the independent modes, and the second contains extra energy caused by mode coupling. This detection is now extended from frequency to time-frequency domain. A comparison between a wavelet transform and our time-frequency technique shows good agreement along with new insight into the time occurrence of the nonlinearities or mode coupling. An application to water surface waves is given in this letter as an example. Index Terms--Amplitude modulation-frequency modulation (AM-FM), horizontal asymmetry, instantaneous amplitude, instantaneous frequency, mode coupling, nonlinear hydrodynamic processes, time-frequency distributions, vertical asymmetry, wave-wave interaction, wind-waves.

Published
2003

17. EUREC 4 A

Author

Stevens, Bjorn, Bony, Sandrine, Farrell, David, Ament, Felix, Blyth, Alan M., Fairall, Chiristopher W., Karstensen, Johannes, Quinn, Patricia K., Speich, Sabrina, Acquistapace, Claudia, Aemisegger, Franziska, Albright, Anna, Bellenger, Hugo, Bodenschatz, Eberhard, Caesar, Kathy-Ann, Chewitt-Lucas, Rebecca, De Boer, Gijs, Delanoë, Julien, Denby, Leif Christopher, Ewald, Florian, Fildier, Benjamin, Forde, Marvin, George, Geet, Gross, Silke, Hagen, Martin, Hausold, Andrea, Heywood, Karen J., Hirsch, Lutz, Jacob, Marek, Jansen, Friedhelm, Kinne, Stefan, Klocke, Daniel, Kölling, Tobias, Konow, Heike, Lothon, Marie, Mohr, Wiebke, Naumann, Ann Kristin, Nuijens, Louise, Olivier, Léa, Pincus, Robert, Pöhlker, Mira L., Reverdin, Gilles, Roberts, Gregory, Schnitt, Sabrina, Sullivan, Peter P., Touzé-Peiffer, Ludovic, Vial, Jessica, Vogel, Raphaela, Alexander, Nicola, Alves, Lyndon, Arixi, Sophian, Asmath, Hamish, Bagheri, Gholamhossein, Bailey, Adriana, Baranowski, Dariusz, Baron, Alexandre, Barrau, Sébastien, Barrett, Paul Alan, Behrendt, Andreas, Bendinger, Arne, Beucher, Florent, Bigorre, Sebastien, Bosser, Pierre, Blossey, P., Bock, Olivier, Bourras, Denis, Bouruet-Aubertot, Pascale, Bower, K, Branger, H, Brennek, M, Brewer, A, Brilouet, P.-E, Brügmann, B, Buehler, S, Burke, E, Burton, R, Böing, S, Calmer, R, Canonici, J.-C, Carton, X, Cato, G, Charles, J, Chazette, Patrick, Chen, Y, Choularton, T, Chuang, P, Clarke, S, Coe, H, Cornet, C, Coutris, P, Couvreux, F, Crewell, S, Cronin, T, Cui, Z, Cuypers, Y, Daley, A, Damerell, G, Dauhut, T, De Graaf, D, De Groot, G, De Szoeke, S, Deneke, H, Desbios, J.-P, Douet, V, Drushka, K, Dütsch, M, Ehrlich, A, Emanuel, K, Emmanouilidis, A, Etienne, J.-C, Etienne-Leblanc, S, Faure, G, Feingold, G, Ferrero, L, Fix, A, Flamant, Cyrille, Flatau, P, Foltz, G, Gadian, A, Galewsky, J, Gallagher, M, Gallimore, P, Gaston, C, Gentemann, C, Geyskens, N, Giez, A, Gourbeyre, C, Grosz, R, Gutleben, M, Güttler, J, Hall, K, Harris, G, Helfer, K, Henze, D, Herbert, C, Holanda, B, Ibanez-Landeta, A, Intrieri, J, Iyer, S, Julien, F, Kalesse, H, Kazil, J, Kellman, A, Kirchner, U, Klingebiel, M, Kremper, L, Kretzschmar, J, Krüger, O, Kurz, A, Körner, M, L'hégaret, P, Lachlan-Cope, T, Laing, A, Landschützer, P, Lang, T, Lange, D, Lange, I, Laplace, C, Laxenaire, R, Le Bihan, C, Leandro, M, Lefevre, N, Lenschow, D, Li, Q, Lloyd, G, Los, S, Losi, N, Lovell, O, Luneau, C, Makuch, P, Malinowski, S, Manta, G, Marinou, E, Marsden, N, Matthieu, L, Maury, N, Mayer, B, Mayers-Als, M, Mazel, Christophe, Mcgeary, W, Mcwilliams, J, Mech, M, Mehlmann, M, Meroni, A, Mieslinger, T, Minikin, A, Avalos, Y, Muller, Caroline, Musat, I, Möller, G, Napoli, A, Neuberger, A, Noone, D, Nordsiek, F, Nowak, J, Oswald, L, Parker, D, Peck, C, Person, R, Plueddemann, A, Pologne, L, Posyniak, M, Prange, M, Pöhlker, C, Pörtge, V, Pöschl, U, Quiñones Meléndez, E, Radtke, J, Ramage, K, Reimann, J, Renault, L, Reus, K, Reyes, A, Ribbe, J, Ringel, M, Ritschel, M, Rocha, C, Rochetin, N, Rollo, C, Röttenbacher, J, Saffin, L, Sandiford, S, Sandu, I, Schemann, V, Schirmacher, I, Schlenczek, O, Schmidt, J, Schröder, M, Schulz, H, Schwarzenboeck, A, Schäfer, M, Sealy, A, Serikov, I, Shohan, S, Siddle, E, Siebesma, A, Späth, F, Stephan, C, Stolla, M, Szkółka, W, Tarot, S, Tetoni, E, Thompson, E, Thomson, J, Tomassini, L, Totems, J, Villiger, L, Walther, A, Webber, B, Wendisch, M, Whitehall, S, Wiltshire, A, Wing, A, Wirth, M, Wiskandt, J, Wolf, K, Worbes, L, Wright, E, Wulfmeyer, V, Young, S, Zhang, D, Zhang, C, Ziemen, F, Zinner, T, Zuidema, P, Zöger, M, Max Planck Institute for Meteorology (MPI-M), Max-Planck-Gesellschaft, Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Caribbean Institute for Meteorology and Hydrology (CIMH), Meteorological Institute [Hamburg], University of Hamburg, National Centre for Atmospheric Science [Leeds] (NCAS), Natural Environment Research Council (NERC), NOAA Earth System Research Laboratory (ESRL), National Oceanic and Atmospheric Administration (NOAA), Helmholtz Centre for Ocean Research [Kiel] (GEOMAR), NOAA Pacific Marine Environmental Laboratory [Seattle] (PMEL), Institute for Geophysics and Meteorology [Köln] (IGM), University of Cologne, Institute for Atmospheric and Climate Science [Zürich] (IAC), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology in Zürich [Zürich] (ETH Zürich), Max Planck Institute for Dynamics and Self-Organization (MPIDS), NOAA Physical Sciences Laboratory (PSL), SPACE - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), University of Leeds, Deutsches Zentrum für Luft- und Raumfahrt (DLR), Deutscher Wetterdienst [Offenbach] (DWD), Ludwig-Maximilians-Universität München (LMU), Laboratoire d'aérologie (LA), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Universität Hamburg (UHH), Max Planck Institute for Marine Microbiology, Delft University of Technology (TU Delft), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Universität zu Köln, École nationale des sciences géographiques (ENSG), Institut National de l'Information Géographique et Forestière [IGN] (IGN)-Université Gustave Eiffel, Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), National Center for Atmospheric Research [Boulder] (NCAR), Institut de Recherche sur les Phénomènes Hors Equilibre (IRPHE), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), TROPO - LATMOS, Institut Pythéas (OSU PYTHEAS), and Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)

Subjects
[SDE]Environmental Sciences, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2020

18. Experimental observation of dark solitons on the surface of water

Author

Chabchoub, A., Kimmoun, O., Branger, H., Hoffmann, N., Proment, D., Onorato, M., Akhmediev, N., Chabchoub, A., Kimmoun, O., Branger, H., Hoffmann, N., Proment, D., Onorato, M., and Akhmediev, N.

Abstract

We present the first ever observation of dark solitons on the surface of water. It takes the form of an amplitude drop of the carrier wave which does not change shape in propagation. The shape and width of the soliton depend on the water depth, carrier frequency, and the amplitude of the background wave. The experimental data taken in a water tank show an excellent agreement with the theory. These results may improve our understanding of the nonlinear dynamics of water waves at finite depths. © 2013 American Physical Society., Alexander von Humboldt-Stiftung, VW-Stiftung International

Published
2020

20. Air-sea turbulent fluxes from a wave-following paltform during six experiments at sea

Author

Bourras, D., Cambra, R., Marié, L., Bouin, M.N., Baggio, L., Branger, H., Beghoura, G., Reverdin, G., Dewitte, Boris, Paulmier, Aurélien, Maes, Christophe, Ardhuin, F., Pairaud, I., Fraunié, P., Luneau, C., and Hauser, D.

Abstract

Turbulent fluxes at the air‐sea interface are estimated with data collected in 2011 to 2017 with a low‐profile platform during six experiments in four regions. The observations were carried out with moderate winds (2–10 m/s) and averaged wave heights of 1.5 m. Most of the time, there was a swell, with an averaged wave age (the ratio between wave phase speed and wind speed) being equal to 2.8 ± 1.6. Three flux calculation methods are used, namely, the eddy covariance (EC), the inertial dissipation (ID), and the bulk methods. For the EC method, a spectral technique is proposed to correct wind data from platform motion. A mean bias affecting the friction velocity (u*) is then evaluated. The comparison between EC u* and ID u* estimates suggests that a constant imbalance term (ϕimb) equal to 0.4 is required in the ID method, possibly due to wave influence on our data. Overall, the confidence in the calculated u* estimates is found to be on the order of 10%. The values of the drag coefficient (CD) are in good agreement with the parameterizations of Smith (1988, https://doi.org/10.1029/JC093iC12p15467) in medium‐range winds and of Edson et al. (2013, https://doi.org/10.1175/JPO‐D‐12‐0173.1) in light winds. According to our data, the inverse wave age varies linearly with wind speed, as in Edson et al. (2013, https://doi.org/10.1175/JPO‐D‐12‐0173.1), but our estimates of the Charnock coefficient do not increase with wind speed, which is possibly related to sampling swell‐dominated seas. We find that the Stanton number is independent from wind speed.

Published
2019

21. A laboratory investigation of electromagnetic bias in sea level measurements by microwave altimeters

Author

Branger, H, Bliven, L, and Ramamonjiarisoa, A

Subjects
Oceanography
Abstract

To contribute to a better understanding of the electromagnetic bias in radar altimetry, a series of experiments was conducted using a focused beam radar set at 13.5-GHz frequency. For pure wind wave fields, the authors found the bias to be a quadratic function of each of the commonly used parameters, namely, the significant wave height, the wind speed, the water elevation skewness, and significant slope. The bias divided by the significant wave height is a linear function of these parameters. The coefficients in bias representation as a function of either the significant wave height or the wind speed are significantly different from values obtained in field experiments. This led to the conclusion that none of the latter parameters can be taken solely to account for all observed bias variations. Instead, dimensionless parameters such as the wave skewness or a dimensionless wave height are shown to be more appropriate.

Published
1991

25. Modulational evolution of water-waves at the atmosphere-ocean interface: some similarities with non-linear optics

Author

Branger, H, Kimmoun, O, Chabchoub, A, Hsu, H. c., Institut de Recherche sur les Phénomènes Hors Equilibre (IRPHE), Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM), Centre for Ocean Engineering Science and Technology, Swinburne University of Technology [Melbourne], National Cheng Kung University (NCKU), Jerome Kasparian, University of Genève, Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), and Branger, Hubert

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, non linear optics, [SDU.OCEAN] Sciences of the Universe [physics]/Ocean, Atmosphere, NLS, [PHYS.MECA.MEFL] Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph], rogue wave, [PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph], Nonlinear Sciences::Pattern Formation and Solitons
Abstract

International audience; The nonlinear Schrodinger equation, who is one of the most significant equations in physics, may model accurately the propagation of nonlinear waves. Some nonlinear waves are known to be unstable to side-band perturbation. This instability, known as the Benjamin-Feir [1] instability or Modulation Instability (MI) in a broader context, can be described by exact pulsating solutions, also referred to as Akhmediev Breathers (ABs). These solutions are of significant importance, since they describe the exact and complete growth and decay cycles of the modulation instability, leading to the Fermi Pasta Ulam [2] (FPU) recurrence. We report here different theoretical, numerical and experimental evidence on AB dynamics, MI, and FPU recurrence, relative to water waves. We will show some similarities with the propagation of non-linear optic waves leading to breathers, dark and gray solitons and rogue waves. The experiments were conducted in different wave tanks and air-sea interaction facilities. Our experimental results show a very good agreement with numerical results and emphasize a broad range of possible applications in nonlinear physics [3], [4], [5].

Published
2015

26. Design of an offshore three-bladed vertical axis wind turbine for wind tunnel experiments

Author

Roy, Sukanta, Branger, H., Luneau, C., Bourras, D., Paillard, B., Roy, Sukanta, Branger, H., Luneau, C., Bourras, D., and Paillard, B.

Abstract

© 2017 ASME. The rapid shrinkage of fossil fuel sources and contrary fast-growing energy needs of social, industrial and technological enhancements, necessitate the need of different approaches to exploit the various renewable energy sources. Among the several technological alternatives, wind energy is one of the most emerging prospective because of its renewable, sustainable and environment friendly nature, especially at its offshore locations. The recent growth of the offshore wind energy market has significantly increased the technological importance of the offshore vertical axis wind turbines, both as floating or fixed installations. Particularly, the class of liftdriven vertical axis wind turbines is very promising; however, the existing design and technology is not competent enough to meet the global need of offshore wind energy. In this context, the project AEROPITCH co-investigated by EOLFI, CORETI and IRPHE aims at the development of a robust and sophisticated offshore vertical axis wind turbine, which would bring decisive competitive advantage in the offshore wind energy market. In this paper, simulations have been performed on the various airfoils of NACA 4-series, 5-series and Selig profiles at different chord Reynolds numbers of 60000, 100000 and 140000 using double multiple streamtube model with tip loss correction. Based on the power coefficient, the best suitable airfoil S1046 has been selected for a 3-bladed vertical axis wind turbine. Besides the blade profile, the turbine design parameters such as aspect ratio and solidity ratio have also been investigated by varying the diameter and chord of the blade. Further, a series of wind tunnel experiments will be performed on the developed wind turbine, and the implementation of active pitch control in the developed turbine will be investigated in future research.

Published
2017

27. Modulation Instability and Phase-Shifted Fermi-Pasta-Ulam Recurrence

Author

Akhmediev, Nail, Branger, H., Kimmoun, O., Hsu, H. C., Li, M. S., Chen, Y. Y., Kharif, C., Onorato, M., Kelleher, E. J. R., Kibler, B., Chabchoub, A., Akhmediev, Nail, Branger, H., Kimmoun, O., Hsu, H. C., Li, M. S., Chen, Y. Y., Kharif, C., Onorato, M., Kelleher, E. J. R., Kibler, B., and Chabchoub, A.

Published
2016

29. A new instrumentation for measuring atmospheric pressure fluctuations in the marine atmospheric boundary layer

Author

Boniface, K., Bourras, Denis, Branger, H., Giovanangeli, J.-P., Hauser, Danièle, Weill, Alain, Legac, C., Géosciences Montpellier, Université des Antilles et de la Guyane (UAG)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Centre d'étude des environnements terrestre et planétaires (CETP), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche sur les Phénomènes Hors Equilibre (IRPHE), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), and Cardon, Catherine

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU.OCEAN] Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, [SDU.ENVI] Sciences of the Universe [physics]/Continental interfaces, environment
Abstract

The proposed work aims at designing a new instrument for studying the behaviour of static pressure fluctuation (SPFs) in the Surface Marine Atmospheric Boundary Layer (SMABL). SPFs are among the least understood meteorological variable. They play an important role in the production or dissipation of turbulent kinetic energy and in wave generation. In addition, they are key to improving parametrizations of momentum exchanges between the sea and the atmosphere. Very few SPF data are currently available which mainly results from inadequate, see inaccurate instrumentation. The reason is that SPF amplitude is of same order of magnitude as interfering signal, in the range of 1-10 Pa. The unwanted signal during SPF measurement comes from dynamic disturbances such as ship motion, waves and turbulence effects. A new type of instrument for measuring SPFs is under development at CETP. It is specifically designed to work onboard dynamically unstable platforms such as ships or moored buoys, for which dynamic pressure effects are large. The selected design consists in a spherical probe that measure the SPFs and a sonic anemometer. Error analysis, simulations of the aerodynamical transfer function of the instrument, as well as preliminary experimental results will be presented. [No additional information in pdf]

Published
2006

30. A New Platform for the Determination of Air–Sea Fluxes (OCARINA): Overview and First Results

Author

Bourras, D., Branger, H., Reverdin, Gilles, Marie, Louis, Cambra, R., Baggio, L., Caudoux, C., Caudal, G., Morisset, S., Geyskens, N., Weill, Alain, Hauser, D., Bourras, D., Branger, H., Reverdin, Gilles, Marie, Louis, Cambra, R., Baggio, L., Caudoux, C., Caudal, G., Morisset, S., Geyskens, N., Weill, Alain, and Hauser, D.

Abstract

The present paper describes a new type of floating platform that was specifically designed for estimating air–sea fluxes, investigating turbulence characteristics in the atmospheric surface boundary layer, and studying wind–wave interactions. With its design, it can be deployed in the open ocean or in shallow-water areas. The system is designed to be used from a research vessel. It can operate for ~10 h as a drifting wave rider and 3 h under power. Turbulence and meteorological instrument packages are placed at a low altitude (1–1.5 m). It was deployed for validation purposes during the Front de Marée, Variabilité (FROMVAR), 2011 experiment off the west coast of Brittany, France. Wind friction velocity and surface turbulent buoyancy flux were estimated using eddy covariance, spectral, bulk, and profile methods. The comparisons of the four methods show a reasonable agreement except for the spectral buoyancy flux. This suggests that the platform design is correct. Also, the wind measured at a fixed height above the sea shows spectral coherence with wave heights, such that wind and swell are in phase, with the largest wind values on top of swell crests. This result in qualitative agreement with current model predictions supports the capability of the Ocean Coupled to Atmosphere, Research at the Interface with a Novel Autonomous platform (OCARINA) to investigate wind–swell interactions.

Published
2014
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31. Gray solitons on the surface of water

Author

Chabchoub, A., Kimmoun, O, Branger, H, Kharif, C, Hoffmann, N P, Onorato, M, Akhmediev, Nail, Chabchoub, A., Kimmoun, O, Branger, H, Kharif, C, Hoffmann, N P, Onorato, M, and Akhmediev, Nail

Abstract

The dynamics of surface gravity water waves can be described by the self-defocusing nonlinear Schrödinger equation. Recent observations of black solitons on the surface of water confirmed its validity for finite, below critical depth. The black soliton i

Published
2014

33. The FETCH experiment: An overview - art. no. 8053

Author

Hauser, Danièle, Branger, H, Bouffies Cloche, S, Despiau, S, Drennan, W, Dupuis, H, Durand, P, Durrieu De Madron, X, Estournel, C, Eymard, L, Flamant, C, Graber, H, Guerin, C, Kahma, K, Lachaud, G, Lefevre, J, Pelon, J, Petterson, H, Piguet, B, Queffeulou, Pierre, Tailliez, D, Tournadre, Jean, and Weill, A

Subjects
Coastal oceanography, Marine atmospheric boundary layer, Remote sensing, Air/sea interactions, Gulf of Lion, Surface ocean waves
Abstract

The "flux, etat de la mer, et tele'de'tection en conditions de fetch variable'' (FETCH) was aimed at studying the physical processes associated with air-sea exchanges and mesoscale oceanic circulation in a coastal region dominated by frequent strong offshore winds. The experiment took place in March-April 1998 in the northwestern Mediterranean Sea (Gulf of Lion). Observations were collected with the R/V L'Atalante, with an air-sea interaction spar (ASIS) buoy, with waverider buoys, and with research aircraft equipped for in situ and remote sensing measurements. The present paper is an introduction to the following special section, which groups 12 papers (including this one) presenting results on turbulent flux measurements at the ocean surface, on the behavior of the marine atmospheric boundary layer, on the ocean waves characteristics, on the ocean circulation, and on remote sensing of surface parameters. This overview presents the background and objectives of FETCH, the experimental setup and operations, and the dominant atmospheric and oceanic conditions and introduces the different papers of the special section.

Published
2003

34. Experimental observation of dark solitons on the surface of water

Author

Chabchoub, A, Kimmoun, O, Branger, H, Hoffmann, N P, Proment, D, Onorato, M, Akhmediev, Nail, Chabchoub, A, Kimmoun, O, Branger, H, Hoffmann, N P, Proment, D, Onorato, M, and Akhmediev, Nail

Abstract

We present the first ever observation of dark solitons on the surface of water. It takes the form of an amplitude drop of the carrier wave which does not change shape in propagation. The shape and width of the soliton depend on the water depth, carrier frequency, and the amplitude of the background wave. The experimental data taken in a water tank show an excellent agreement with the theory. These results may improve our understanding of the nonlinear dynamics of water waves at finite depths.

Published
2013

35. Gray solitons on the surface of water

Author

Chabchoub, A., primary, Kimmoun, O., additional, Branger, H., additional, Kharif, C., additional, Hoffmann, N., additional, Onorato, M., additional, and Akhmediev, N., additional

Published
2014
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39. A time-frequency application with the Stokes-Woodward technique

Author

Elfouhaily, Tanos, Guignard, S, Branger, H, Thompson, D, Chapron, Bertrand, Vandemark, D, Elfouhaily, Tanos, Guignard, S, Branger, H, Thompson, D, Chapron, Bertrand, and Vandemark, D

Abstract

In a recent paper, we have generalized Woodward's theorem and applied it to the case of random signals jointly modulated in amplitude and frequency. This generalization yields a new spectral technique to estimate the amount of energy due to mode coupling without calling for higher order statistics. Two power spectra are detected; the first is related to the independent modes, and the second contains extra energy caused by mode coupling. This detection is now extended from frequency to time-frequency domain. A comparison between a wavelet transform and our time-frequency technique shows good agreement along with new insight into the time occurrence of the nonlinearities or mode coupling. An application to water surface waves is given in this letter as an example.

Published
2003
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44. An Assessment of Veering Wind Effects On Scatterometry From the Sea-surface

Author

UCL, Bliven, LF., Billat, V., Sobieski, Piotr, Guissard, AC., Branger, H., Giovanangeli, JP., UCL, Bliven, LF., Billat, V., Sobieski, Piotr, Guissard, AC., Branger, H., and Giovanangeli, JP.

Abstract

To characterize scatterometer returns from the sea surface near meteorological fronts, we investigated microwave scattering from seas in which long waves are at oblique angles to short waves. We simulate the effects of veering winds on C- and K-u-band scatterometers by using models in which the short waves align with the wind friction velocity u*, but the long waves are at oblique angles to the u* direction. The analysis reveals two main effects due to the rotation of the long wave slope probability density distribution. Azimuthally averaged normalized radar cross-section a(0) decreases as the oblique angle increases. Additionally, two regimes exist. In the small angle regime, azimuthal scans of normalized radar cross-section sigma degrees exhibit features similar to the classic double-maxima pattern for non-veering wind conditions, but the axis of sigma degrees maxima is rotated toward the long-wave axis. In the large angle regime, more than two maxima are apparent in azimuthal scans. Therefore it may be inappropriate to use standard three term Fourier cosine models for some veering wind conditions.

Published
1995

50. Gravity wave amplification and phase crest re-organization over a shoal.

Author

Jarry, N., Rey, V., Gouaud, F., Lajoie, D., Pelinovsky, E., Branger, H. B., and Maximov, V.

Subjects
BANKS (Oceanography), GRAVITY waves, SURFACE waves (Fluids), MEASUREMENT, CROSS-sectional method, PHOTOGRAPHY, WAVE diffraction
Abstract

In this experimental work, both wave amplification and phase evolution, due to a submerged mound, are studied. In addition to the classical surface wave measurements, the experimental study takes advantage of photographs that underline crest re-organization above and down-wave the shoal. In particular, together with wave amplification up to more than twice the incident wave, a wave steepening is observed in certain conditions in both the wave direction and in the cross-section. Due to a phase crest separation downstream of the shoal, steepening in the crossshore direction is enhanced (up to 30% above the steepening along the main direction of propagation). Physical aspects are discussed through the analysis of the diffraction effects on the wave properties. [ABSTRACT FROM AUTHOR]

Published
2011
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