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Showing 1 to 20 of 22 for “"Streamfunction"”.
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Finite Elements for the Quasi-Geostrophic Equations of the Ocean
… of the QGE have been developed for the streamfunction-vorticity formulation. The reason is simple: The streamfunction-vorticity formulation yields a second order \\emph{partial differential equation (PDE)}, whereas the streamfunction formulation yields a fourth order PDE. Thus, although …
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Development of a two-dimensional model of blood microcirculation flows
… This model formulation allows for the use of the streamfunction-vorticity formulation of the Navier-Stokes equation, which offers simplification to boundary conditions and also allows for the use of a non-uniform, collocated mesh. A streamfunction vorticity formulation of the Immersed Boundary …
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Geostrophic vortex dynamics
… perspective. The analysis of the topology of the streamfunction in a frame of reference rotating with the instantaneous angular velocity of the vorticity distribution (the corotating frame) is shown to yield new powerful insights on the nonlinear evolution of the vorticity field. In particular, …
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Hydrodynamic Instability of Fluid Flow Through Homogeneous Porous Media
… or computational studies. A new porosity-based streamfunction transformation is introduced, similar in aspects to the density-based transformations used in compressible flows. The porosity is then assumed to be a function of flow Reynolds number. The equation for the linearized disturbance …
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Dynamics and Predictability of the Intraseasonal Disturbances
… background conditions. The daily 500-mb global streamfunction fields are used. The year-to-year variations of the intraseasonal variability are closely related to the variations of the corresponding seasonal-mean flow.
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Computational simulation of buoyancy-driven flows using vortex methods
… field is then computed using a vorticity-streamfunction scheme similar to the vortex-in-cell approach. Complete simulations for a variety of Rayleigh-Taylor stability problems are presented, as are preliminary results for Rayleigh-Bernard flows.
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Estimating open-ocean boundary conditions : sensitivity studies
… conditions. Successively, the boundary values of streamfunction and vorticity are included among the control variables and estimated together with the initial conditions. Experiments are performed with various choices of scaling and first guess for the control variables, and various observational …
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Working Up Hills: Dynamics over Sloping Topography with Bottom-Enhanced Diffusion
… A variational problem was created from derived streamfunction-vorticity equations plus advection-diffusion of a sole tracer, potential temperature. Preliminary simulations confirmed that both models were capable of simulating the desired phenomena, notably an upslope flow along the topography, …
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Circulations and water mass balances in the Brazil Basin
… we find that the application of the Montgomery streamfunction to the isopycnal surfaces induces an error which can not be ignored in some regions in the ocean. The error arises from the sloping effect of the specific volume anomaly along isopycnal surfaces. By including the major part of this …
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Numerical study of linearized unsteady stagnation flow
… two-dimensional and three-dimensional methods. A streamfunction-vorticity formulation is evaluated for two-dimensional linearized stagnation flows. In addition, a primitive variable formulation is developed for three-dimensional linearized stagnation flows. The two methods are tested for grid …
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Hydraulics and instabilities of quasi-geostrophic zonal flows
… relationship between potential vorticity and streamfunction. Using theorems for uniqueness and existence of two point boundary value problems, a necessary condition for the existence of multiple states was established. Only certain flows with non-constant, negative dQ(ψ)/dψ have alternate …
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Baroclinic vortices over a sloping bottom
… to identify waves and vortices from the streamfunction fields, because the waves are present in both layers.
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Interannual variability of the Atlantic Hadley circulation in boreal summer and its impacts on tropical cyclone activity
… circulation (HC) in terms of the meridional streamfunction. The interannual variability of the Atlantic HC in boreal summer was examined using the EOF analysis. The leading mode (M1), explaining more than 45% of the variances, is associated with the intensity change of the ITCZ. M1 is …
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Numerical Simulation And Control Of Thermocapillary Convection In Cavities And Liquid Layers
… is based on a coordinate transformation method, streamfunction vorticity formulation, and second-order finite-difference discretization. The unknown physical domain is mapped onto a rectangular computational domain, with the explicit form of the mapping function not being known. The field …
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Mixing And Transport In The Kelvin-Stuart Cat Eyes Driven Flow Using The Topological Approximation Method
… 2ð spatial periodicity in x with an unperturbed streamfunction of H(x, y) = ln(cosh y + A cos x) – ln(1+A). The driven flow has perturbation terms of å sin(ùt) in both the x and y directions. Lobe dynamics transport theory states that transport occurs through the transfer of turnstile lobes, and …
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Assimilation of altimeter data in a quasi-geostrophic model of the Gulf Stream system : a dynamical perspective
… while in the second experiment the total surface streamfunction field (mean + eddies) has been used. We have found that the mean component of the surface data determines, to a large extent, the structure of the flow field in the subsurface layers, while the eddy field, as well as the …
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Multivariate Correlations: Balance Operators and Variable Localization in Ensemble Data Assimilation
… propagate information one way, for example, from streamfunction to temperature, but not vice versa as in the hybrid 4DEnVar. Many applications contain variables that are physically unrelated and should not be correlated, but contain nonzero correlations. The second part of this dissertation …
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Studies of climate variability in a simple coupled model
… variability additionally generates a baroclinic streamfunction as well as baroclinic Rossby waves at the eastern boundary of the basin. The former is slowly advected by the mean flow while the latter propagates towards the western boundary, inducing a feedback on the atmosphere with a delay of …
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Driving the ocean's overturning : an adjoint sensitivity study
… the maximum value of the meridional overturning streamfunction. The role of surface buoyancy forcing on the overturning's strength depends on the formulation of the surface boundary conditions. The sensitivities are confined to high latitudes and the vicinity of convection sites when the surface …
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Data-Driven Variational Multiscale Reduced Order Modeling of Turbulent Flows
… (FTLE)), but also Eulerian fields (e.g., the streamfunction). We emphasize that the new Lagrangian ROMs do not employ any closure modeling to model the effect of discarded modes (which is standard procedure for low-dimensional ROMs of complex nonlinear systems). Thus, the dramatic increase in …
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