http://hdl.handle.net/2117/5766 2013-05-24T11:49:37Z http://hdl.handle.net/2117/16779 Title: Convectons Authors: Alonso Maleta, María Aránzazu; Batiste Boleda, Oriol; Knobloch, Edgar; Mercader Calvo, María Isabel Abstract: A horizontal layer containing a miscible mixture of two fluids can generate dissipative solitons called convectons when heated from below. The physics of the system leading to this behavior is explained, and the properties of the resulting convectons are described. The convectons are shown to be present in a parameter regime known as the pinning region containing a multiplicity of stable convectons of odd and even parity. These lie on solution branches that snake back and forth across the pinning region and illustrate a phenomenon known as homoclinic snaking. Examples of single pulse and multipulse convectons in periodic and closed containers are exhibited and compared with similar states described by the Swift-Hohenberg equation. Time-dependent states in the form of localized traveling waves are computed and distinguished from convectons that drift. 2012-10-22T15:01:19Z http://hdl.handle.net/2117/15363 Title: Mixing efficiency in buoyant flows Authors: Redondo Apraiz, José Manuel; Lopez Gonzalez-Nieto, Pilar; Díez Rilova, Margarita 2012-02-24T14:31:04Z http://hdl.handle.net/2117/15347 Title: Swimming propulsion due to vortices Authors: Redondo Apraiz, José Manuel; Arellano, Raul; Carrillo Cortés, José Alejandro; Matulka, Annia; Ben Mahjoub, Otman; Sekula, Emil 2012-02-23T19:52:55Z http://hdl.handle.net/2117/6995 Title: The role of surface rollers on the formation of surfzone transverse sand bars Authors: Ribas Prats, Francesca; Swart, Huib E. de; Calvete Manrique, Daniel; Falqués Serra, Albert Abstract: A morphodynamic model has been developed to gain more fundamental knowledge about the formation of transverse finger sand bars. The model describes the feedback between waves, rollers, depth-averaged currents and bed evolution, so that self-organized processes can develop. The wave and bathymetric conditions measured at Egmond site are firstly applied and the modeled longshore current and wave height are compared with field data of that beach. Subsequently, the wave and bathymetric conditions measured at Noordwijk site are used to compare model results with the up-current oriented bars observed there. Realistic positive feedback leading to formation of the observed bars only occurs if the resuspension of sediment due to bore turbulence is included in the model. The modeled wavelength, crest orientation and growth rate agree with data but the model overestimates the migration rates. 2010-04-20T09:55:11Z http://hdl.handle.net/2117/6560 Title: The role of the depth-averaged concentration in coastal morphodynamics Authors: Calvete Manrique, Daniel; Falqués Serra, Albert; Swart, Huib E. de; Dodd, Nicholas; Ribas Prats, Francesca; Garnier, Roland Abstract: In this contribution a discussion is presented on the development of self-organized coastal morphodynamic patterns which are due to the joint action of gradients in the depth-integrated concentration and the flow. This is done in the context of a depth-averaged shallow water model. Two physical mechanisms produce deposition-erosion patterns. Deposition either occurs where the current flows from high to low depth-averaged concentrations (1) or where the flow diverges (2). If flow conditions are quasi steady (i.e., the time scale on which bedforms evolve is much larger than the hydrodynamic time scales) only the former mechanism contributes to the formation of bottom patterns. 2010-03-05T16:11:05Z