Archivo Digital UPM: No conditions. Results ordered -Date Deposited. 2020-02-22T08:08:06ZEPrintshttp://oa.upm.es/style/images/logo-archivo-digital.pnghttp://oa.upm.es/2019-03-26T13:03:29Z2019-03-26T13:03:29Zhttp://oa.upm.es/id/eprint/53493This item is in the repository with the URL: http://oa.upm.es/id/eprint/534932019-03-26T13:03:29ZPattern selection in a horizontally vibrated containerWe present results of an experimental and numerical investigation of the patterns realized by surface waves within an open rectangular container subjected to horizontal vibrations at frequencies of 40?100 Hz. The first instability exhibited by the primary harmonic wave field is subharmonic, and may be identified with the cross-wave instability often seen in wave tank experiments. We show that, contrary to common theoretical and experimental assumptions, and despite their name, these subharmonic waves are not oriented crosswise, but at an intermediate angle with respect to the axis of vibration. Hence, the pattern selection problem for horizontally forced Faraday waves is more complex than has previously been assumed. We establish the robustness of this obliquely oriented surface wave pattern by varying the forcing frequency and amplitude, the fluid viscosity, the fluid depth, and the boundary conditions. Previous work on cross-waves is reviewed and discussed in relation to the current results. Finally, numerical simulations using a reduced model with an appropriate forcing term are used to support the generality of the experimental observations.Jeffrey Brent PorterIgnacio Tinao Perez-MiraveteAna Laveron SimavillaCarlos A. Lopez2019-02-04T12:43:26Z2019-04-23T13:38:21Zhttp://oa.upm.es/id/eprint/53496This item is in the repository with the URL: http://oa.upm.es/id/eprint/534962019-02-04T12:43:26ZInstabilities of vibroequilibria in rectangular containersVibroequilibria theory, based on minimizing an averaged energy functional, predicts the quasi-equilibrium shape that a fluid volume will take when subjected to high-frequency vibrations. Here we present a detailed comparison of the predictions of vibroequilibria theory with the results of direct numerical simulations in horizontally vibrated rectangular containers, finding very good agreement over a range of parameters. The calculations also reveal an important difference in the behavior between small and large fluid volumes. With dimensionless volume larger than about 0.36, the symmetric vibroequilibria solution suffers a saddle-node instability prior to contact with the container bottom. This saddle-node bifurcation is analyzed using a simplified family of surfaces and shown to persist when gravity is included. Finally, an investigation of dynamic effects is presented, where a strong correlation is found between modulated subharmonic surface waves and the first odd sloshing mode. At large enough amplitude, this sloshing destroys the underlying vibroequilibria state and thus represents a possible instability for vibroequilibria in low viscosity fluids.Jose Javier Fernandez FraileIgnacio Tinao Perez-MiraveteJeffrey Brent PorterAna Laveron Simavilla