DF - Dinàmica No Lineal de Fluids
http://hdl.handle.net/2117/1085
Thu, 30 Mar 2017 23:04:49 GMT2017-03-30T23:04:49ZOn the physics behind coastal morphodynamic patterns
http://hdl.handle.net/2117/103092
On the physics behind coastal morphodynamic patterns
Ribas Prats, Francesca; Falqués Serra, Albert; de Swart, Huib E.; Dodd, Nicholas; Garnier, Roland Charles; Calvete Manrique, Daniel
Thu, 30 Mar 2017 09:53:19 GMThttp://hdl.handle.net/2117/1030922017-03-30T09:53:19ZRibas Prats, FrancescaFalqués Serra, Albertde Swart, Huib E.Dodd, NicholasGarnier, Roland CharlesCalvete Manrique, DanielModelling of mega-nourishments
http://hdl.handle.net/2117/103090
Modelling of mega-nourishments
Arriaga García, Jaime Alonso; Rutten, Jantien; Ribas Prats, Francesca; Ruessink, Gerben; Falqués Serra, Albert
The Sand Engine is a hook-shaped mega-nourishment (21.5 Mm³) located in the Dutch coast with
an alongshore length of 2.4 km and an offshore extension of 1 km. The mega-nourishment project
was initiated as a coastal protection measure on decadal time scales to maintain the coastline under
predicted sea level rise (Stive et al., 2013).
In the present work we use the Q2Dmorfo model (van den Berg, et al., 2012) to predict the
dynamics of idealized mega-nourishments, after validation of the model against the evolution of
the Sand Engine
Thu, 30 Mar 2017 09:42:21 GMThttp://hdl.handle.net/2117/1030902017-03-30T09:42:21ZArriaga García, Jaime AlonsoRutten, JantienRibas Prats, FrancescaRuessink, GerbenFalqués Serra, AlbertThe Sand Engine is a hook-shaped mega-nourishment (21.5 Mm³) located in the Dutch coast with
an alongshore length of 2.4 km and an offshore extension of 1 km. The mega-nourishment project
was initiated as a coastal protection measure on decadal time scales to maintain the coastline under
predicted sea level rise (Stive et al., 2013).
In the present work we use the Q2Dmorfo model (van den Berg, et al., 2012) to predict the
dynamics of idealized mega-nourishments, after validation of the model against the evolution of
the Sand EngineLong-term and large-scale modeling of mega-nourishments
http://hdl.handle.net/2117/103088
Long-term and large-scale modeling of mega-nourishments
Arriaga García, Jaime Alonso; Rutten, Jantien; Ribas Prats, Francesca; Ruessink, Gerben; Falqués Serra, Albert
The Sand Engine, ZM (Zandmotor), is a hook-shaped mega-nourishment (21.5 millions m³) located on the
Dutch coast with an alongshore length of 2.4 km and an offshore extension of 1 km. The mega-nourishment project was
initiated as a coastal protection measure on decadal time scales to maintain the coastline under predicted sea level rise.
It follows the philosophy of working in harmony with the forces of nature by taking advantage of the longshore
transport as the main distributor of sand along the adjacent coast (Stive et al., 2013).
In the present contribution we use the Q2Dmorfo model (van den Berg, et al., 2012) to predict the long-term
dynamics of the ZM.
Thu, 30 Mar 2017 09:26:20 GMThttp://hdl.handle.net/2117/1030882017-03-30T09:26:20ZArriaga García, Jaime AlonsoRutten, JantienRibas Prats, FrancescaRuessink, GerbenFalqués Serra, AlbertThe Sand Engine, ZM (Zandmotor), is a hook-shaped mega-nourishment (21.5 millions m³) located on the
Dutch coast with an alongshore length of 2.4 km and an offshore extension of 1 km. The mega-nourishment project was
initiated as a coastal protection measure on decadal time scales to maintain the coastline under predicted sea level rise.
It follows the philosophy of working in harmony with the forces of nature by taking advantage of the longshore
transport as the main distributor of sand along the adjacent coast (Stive et al., 2013).
In the present contribution we use the Q2Dmorfo model (van den Berg, et al., 2012) to predict the long-term
dynamics of the ZM.Using archives of past floods to estimate future flood hazards
http://hdl.handle.net/2117/103084
Using archives of past floods to estimate future flood hazards
Swierczynski, Tina; Ionita, Monica; Pino González, David
Worldwide, floods cause greater economic damage and loss of human life than any other type of natural disaster. We urgently need better assessments of flood hazards to reduce the societal impact of extreme floods caused by Earth’s rapidly changing climate, among other factors.
One way of assessing flood hazards is to examine past floods using the records provided by hydrological instruments. We can extend this knowledge back through the Holocene period or beyond using historical documents and natural archives (including alluvial, marine, and lake sediments; tree rings; and cave formations). These extended records can provide valuable information about long-term flood trends.
Thu, 30 Mar 2017 09:09:23 GMThttp://hdl.handle.net/2117/1030842017-03-30T09:09:23ZSwierczynski, TinaIonita, MonicaPino González, DavidWorldwide, floods cause greater economic damage and loss of human life than any other type of natural disaster. We urgently need better assessments of flood hazards to reduce the societal impact of extreme floods caused by Earth’s rapidly changing climate, among other factors.
One way of assessing flood hazards is to examine past floods using the records provided by hydrological instruments. We can extend this knowledge back through the Holocene period or beyond using historical documents and natural archives (including alluvial, marine, and lake sediments; tree rings; and cave formations). These extended records can provide valuable information about long-term flood trends.Inertial waves in rapidly rotating flows: a dynamical systems perspective
http://hdl.handle.net/2117/102980
Inertial waves in rapidly rotating flows: a dynamical systems perspective
López Moscat, Juan Manuel; Marqués Truyol, Francisco
An overview of recent developments in a wide variety of enclosed rapidly rotating flows is presented. Highlighted is the interplay between inertial waves, which have been predicted from linear inviscid considerations, and the viscous boundary layer dynamics which result from instabilities as the nonlinearities in the systems are increased. Further, even in the absence of boundary layer instabilities, nonlinearity in the system often leads to complicated interior flows due to subcritical instabilities, Eckhaus bands and heteroclinic dynamics. The ensuing spatio-temporally complex dynamics is analysed in terms of equivariant dynamical systems, providing a general perspective for the wide range of dynamics involved.
Tue, 28 Mar 2017 14:51:51 GMThttp://hdl.handle.net/2117/1029802017-03-28T14:51:51ZLópez Moscat, Juan ManuelMarqués Truyol, FranciscoAn overview of recent developments in a wide variety of enclosed rapidly rotating flows is presented. Highlighted is the interplay between inertial waves, which have been predicted from linear inviscid considerations, and the viscous boundary layer dynamics which result from instabilities as the nonlinearities in the systems are increased. Further, even in the absence of boundary layer instabilities, nonlinearity in the system often leads to complicated interior flows due to subcritical instabilities, Eckhaus bands and heteroclinic dynamics. The ensuing spatio-temporally complex dynamics is analysed in terms of equivariant dynamical systems, providing a general perspective for the wide range of dynamics involved.Flexible rod design for educational wind balance
http://hdl.handle.net/2117/102821
Flexible rod design for educational wind balance
Raush Alviach, Gustavo Adolfo; Castilla López, Roberto; Gámez Montero, Pedro Javier; Wojciechowski, Jakub; Codina Macià, Esteban
This article provides a technical description of a flexible hinge for wind tunnel rigs. For academic purposes, the device was integrated into several rod flexures to build a home-made external wind balance system. The cylindrical elastic element incorporates several notches, and the flexure linkage is able to transmit force in the main axial direction without hindering perpendicular movement. The flexural element described here is simple and easily manufactured, and can also be used with other types of wind balance. The flexure described in this article has similar functionality to those mentioned in the reference section, but has a more compact element. The project's effectiveness was demonstrated in a series of experimental comparisons of forces and moments measured on a wing using the N.A.C.A. Clark-Y airfoil profile.
This is a copy of the author 's preprint version of an article published in the journal Experimental techniques. The final publication is available at Springer via http://dx.doi.org/10.1007/s40799-016-0017-9
Thu, 23 Mar 2017 11:45:22 GMThttp://hdl.handle.net/2117/1028212017-03-23T11:45:22ZRaush Alviach, Gustavo AdolfoCastilla López, RobertoGámez Montero, Pedro JavierWojciechowski, JakubCodina Macià, EstebanThis article provides a technical description of a flexible hinge for wind tunnel rigs. For academic purposes, the device was integrated into several rod flexures to build a home-made external wind balance system. The cylindrical elastic element incorporates several notches, and the flexure linkage is able to transmit force in the main axial direction without hindering perpendicular movement. The flexural element described here is simple and easily manufactured, and can also be used with other types of wind balance. The flexure described in this article has similar functionality to those mentioned in the reference section, but has a more compact element. The project's effectiveness was demonstrated in a series of experimental comparisons of forces and moments measured on a wing using the N.A.C.A. Clark-Y airfoil profile.The potential of the sea breeze for wind energy generation in peri-urban coastal areas using small wind turbines
http://hdl.handle.net/2117/102569
The potential of the sea breeze for wind energy generation in peri-urban coastal areas using small wind turbines
Rojas Gregorio, José Ignacio; Cabrera Agudo, Barbara; Mazón Bueso, Jordi
This work investigates the potential of the sea breeze for wind energy generation with small wind turbines. For this purpose, we used wind data recorded in the Llobregat Delta (NE of the Iberian Peninsula) from 1993 to 2010 and turbine power curves obtained from QBlade, FAST and AeroDyn freeware tools, and from the manufacturer. The HP-600W turbine, with hub-height 8 m, would deliver 126 kWh in a year (53 kWh during the sea breeze period, i.e., March 1 to September 30, 10 to 19h LT), with average power of 14 W (27 W). The results for the entire year agree with data measured in situ in 2015, but it is not the case for the sea breeze period. Therefore, more research is necessary to validate completely the proposed approach, and to confirm the real potential of the sea breeze for micro-generation in a peri-urban coastal area like the one under study, where large wind farms are not feasible.
Thu, 16 Mar 2017 10:38:04 GMThttp://hdl.handle.net/2117/1025692017-03-16T10:38:04ZRojas Gregorio, José IgnacioCabrera Agudo, BarbaraMazón Bueso, JordiThis work investigates the potential of the sea breeze for wind energy generation with small wind turbines. For this purpose, we used wind data recorded in the Llobregat Delta (NE of the Iberian Peninsula) from 1993 to 2010 and turbine power curves obtained from QBlade, FAST and AeroDyn freeware tools, and from the manufacturer. The HP-600W turbine, with hub-height 8 m, would deliver 126 kWh in a year (53 kWh during the sea breeze period, i.e., March 1 to September 30, 10 to 19h LT), with average power of 14 W (27 W). The results for the entire year agree with data measured in situ in 2015, but it is not the case for the sea breeze period. Therefore, more research is necessary to validate completely the proposed approach, and to confirm the real potential of the sea breeze for micro-generation in a peri-urban coastal area like the one under study, where large wind farms are not feasible.Periodic orbits in tall laterally heated rectangular cavities
http://hdl.handle.net/2117/102448
Periodic orbits in tall laterally heated rectangular cavities
Net Marcé, Marta; Sánchez Umbría, Juan
This study elucidates the origin of the multiplicity of stable oscillatory flows detected by time integration in tall rectangular cavities heated from the side. By using continuation techniques for periodic orbits, it is shown that initially unstable branches, arising at Hopf bifurcations of the basic steady flow, become stable after crossing Neimark-Sacker points. There are no saddle-node or pitchfork bifurcations of periodic orbits, which could have been alternative mechanisms of stabilization. According to the symmetries of the system, the orbits are either fixed cycles, which retain at any time the center symmetry of the steady flow, or symmetric cycles involving a time shift in the global invariance of the orbit. The bifurcation points along the branches of periodic flows are determined. By using time integrations, with unstable periodic solutions as initial conditions, we determine which of the bifurcations at the limits of the intervals of stable periodic orbits are sub- or supercritical.
Tue, 14 Mar 2017 13:11:34 GMThttp://hdl.handle.net/2117/1024482017-03-14T13:11:34ZNet Marcé, MartaSánchez Umbría, JuanThis study elucidates the origin of the multiplicity of stable oscillatory flows detected by time integration in tall rectangular cavities heated from the side. By using continuation techniques for periodic orbits, it is shown that initially unstable branches, arising at Hopf bifurcations of the basic steady flow, become stable after crossing Neimark-Sacker points. There are no saddle-node or pitchfork bifurcations of periodic orbits, which could have been alternative mechanisms of stabilization. According to the symmetries of the system, the orbits are either fixed cycles, which retain at any time the center symmetry of the steady flow, or symmetric cycles involving a time shift in the global invariance of the orbit. The bifurcation points along the branches of periodic flows are determined. By using time integrations, with unstable periodic solutions as initial conditions, we determine which of the bifurcations at the limits of the intervals of stable periodic orbits are sub- or supercritical.Maxwell equations in the Debye potential formalism
http://hdl.handle.net/2117/102159
Maxwell equations in the Debye potential formalism
Fayos Vallés, Francisco; Llanta Salleras, Estanislao; Llosa, J
The authors propose a method for computing the electromagnetic test-field created by a given distribution of charges and currents using the Debye potential formalism in curved space-times. This framework has been applied explicitly to the Schwarzschild case.
Wed, 08 Mar 2017 18:24:18 GMThttp://hdl.handle.net/2117/1021592017-03-08T18:24:18ZFayos Vallés, FranciscoLlanta Salleras, EstanislaoLlosa, JThe authors propose a method for computing the electromagnetic test-field created by a given distribution of charges and currents using the Debye potential formalism in curved space-times. This framework has been applied explicitly to the Schwarzschild case.Nonlinear and detuning effects of the nutation angle in precessionally-forced rotating cylinder flow
http://hdl.handle.net/2117/101564
Nonlinear and detuning effects of the nutation angle in precessionally-forced rotating cylinder flow
Lopez Moscat, Juan Manuel; Marqués Truyol, Francisco
The flow in a rapidly rotating cylinder forced to precess through a nutation angle a
is investigated numerically, keeping all parameters constant except a, and tuned to a
triadic resonance at a = 1º. When increasing a, the flow undergoes a sequence of well-
characterized bifurcations associated with triadic resonance, involving heteroclinic and
homoclinic cycles, for a up to about 4º. For larger a, we identify two chaotic regimes.
In the first regime, with a between about 4º and 27º, the bulk flow retains remnants of
the helical structures associated with the triadic resonance, but there are strong nonlinear
interactions between the various azimuthal Fourier components of the flow. For the larger
a regime, large detuning effects lead to the triadic resonance dynamics being completely
swamped by boundary layer eruptions. The azimuthal mean flow at large angles results in a
large mean deviation from solid-body rotation and the flow is characterized by strong shear
at the boundary layers with temporally chaotic eruptions.
Fri, 24 Feb 2017 15:42:52 GMThttp://hdl.handle.net/2117/1015642017-02-24T15:42:52ZLopez Moscat, Juan ManuelMarqués Truyol, FranciscoThe flow in a rapidly rotating cylinder forced to precess through a nutation angle a
is investigated numerically, keeping all parameters constant except a, and tuned to a
triadic resonance at a = 1º. When increasing a, the flow undergoes a sequence of well-
characterized bifurcations associated with triadic resonance, involving heteroclinic and
homoclinic cycles, for a up to about 4º. For larger a, we identify two chaotic regimes.
In the first regime, with a between about 4º and 27º, the bulk flow retains remnants of
the helical structures associated with the triadic resonance, but there are strong nonlinear
interactions between the various azimuthal Fourier components of the flow. For the larger
a regime, large detuning effects lead to the triadic resonance dynamics being completely
swamped by boundary layer eruptions. The azimuthal mean flow at large angles results in a
large mean deviation from solid-body rotation and the flow is characterized by strong shear
at the boundary layers with temporally chaotic eruptions.