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Showing 1 to 20 of 30 for “"Pseudo-spectral"”.
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Examining Plasma Instabilities as Ionospheric Turbulence Generation Mechanisms Using Pseudo-Spectral Methods
… the solar eclipse. A novel 2D electrostatic pseudo-spectral fluid model is developed to study the growth of these two instabilities and the problem of ionospheric turbulence in general. To focus on the ionospheric turbulence, a set of perturbed governing equations are derived. The model …
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Three-Dimensional Fluid Simulations of Mid-Latitude Ionospheric Processes with Hybrid Chebyshev/Fourier Pseudo-Spectral Methods
… relative to the density gradient. Numerical spectral analysis results are presented and compared to recent experimental observations.par A newly developed three-dimensional (3D) electrostatic fluid model extends these investigations to capture the behavior and evolution of ionospheric plasma …
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On matrix-free pseudo-arclength continuation methods applied to a nonlocal partial differential equation in 1+1D with pseudo-spectral time-stepping
… with periodic boundary conditions [5]. We apply pseudo-spectral methods to numerically integrate initial states of the populations given as small perturbations from a homogeneous steady state from which bifurcations and dynamics have been studied from a linear and weakly nonlinear analysis …
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Simulation of Turbulent Flows Using Nodal Integral Method
… k = 1 are compared with those obtained using the pseudo spectral method. The comparison shows good agreement and also shows that results obtained with similar grid sizes and time steps match very well with those obtained using pseudo spectral method. New results are obtained for k = 2, and the …
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Large eddy simulation of subsonic mixing layers
… 3-D simulations, different finite-difference and pseudo-spectral schemes are tested. The (2, 4) MacCormack Scheme developed by Gottlieb and Turkel (1976) shows the best overall performance. It is very fast and supplies enough but not excessive artificial dissipation. Though slower than MacCormack …
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Numerical Investigation of turbulent coupling boundary layer of air-water interaction flow
… and shear stress condition across the interface. Pseudo-spectral method is used in each flow subdomain with Fourier expansion in streamwise and spanwise directions and finite difference in vertical direction. Statistically quasi-steady flow properties, such as mean velocity profiles, turbulent …
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Numerical Simulations Of Black Hole Binaries: Second Order Spectral Methods
Current spectral simulations of Einstein's equations require writing the system in first-order form, potentially introducing instabilities and inefficiencies. This work presents a new penalty method for pseudo-spectral evolutions of second order in space wave equations. The penalties are …
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Co-design Investigation and Optimization of an Oscillating-Surge Wave Energy Converter
… power take-off components and controls using a pseudo-spectral method for each geometry. An investigation of electrical power and mechanical power maximization also outlines the contrasting nature of the two objectives to illustrate electrical power maximization's importance for identifying …
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The generation of African waves
… season of intense wave activity. A linearized, pseudo-spectral, primitive equation model is used to simulate the response of the observed jet to perturbations on the scale of African waves. Results show that the jet is unstable due to both its horizontal and vertical shears. The sub adiabatic …
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Numerical and asymptotic modeling of evolving nonlinear ocean surface wave fields
… numerical simulations via a Fourier pseudo-spectral method are discussed. The simulations are initialized with a well-known JONSWAP wave spectrum and different angular distributions are employed. Both deterministic and Monte-Carlo simulations and the corresponding analysis were …
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Modeling wind forcing in phase resolving simulation of nonlinear wind waves
… broadband wind waves based on the High Order Spectral (HOS) method (Dommermuth and Yue 1987). The original HOS method, which is a nonlinear pseudo-spectral numerical technique for phase resolving simulation of free regular waves, is extended to simulation of wind forced irregular broadband …
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Numerical Simulation of Ion-Cyclotron Turbulence Generated by Artificial Plasma Cloud Release
… nonlinear evolution of this turbulence. Fourier pseudo-spectral methods are combined with finite difference methods to solve the electron momentum equations. Time integration is accomplished by a 4th-order Runge-Kutta scheme or predicator-corrector method. The numerical results show good …
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Surface textures and non-Newtonian fluids for decreased friction in full film lubrication
… mathematical model for the lubricated system. A pseudo-spectral method is used to solve the Reynolds equation in cylindrical coordinates. Exponential convergence is shown with this solution method and favorable results to the experimental results are shown, validating the numerical method for use …
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Tidal Dissipation in Extrasolar Planets
… use of an ellipsoidal coordinate system with a pseudo-spectral method to solve the partial differential equation that governs the inertial oscillations. We show that, this technique produces highly accurate solutions when the density profile is smooth. In particular, the lines of nodes are …
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Dynamics and Statics of Liquid-Liquid and Gas-Liquid interfaces on Non-Uniform Substrates at the Micron and Sub-Micron Scales
… PDE system and constraints were solved using a pseudo-spectral method. Both 2D and 3D models predict that in order for a doubly confined bubble to grow in a super-saturated solution it must first increase its curvature; this is in contrast to a free-floating bubble whose curvature always …
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Instability of Oscillatory Flow in Ducts and Applications to Solid -Propellant Rocket Aeroacoustics
… approach, linear stability theory together with pseudo spectral method is used to obtain unstable flow regimes for ducted flows with injection and acoustic oscillations. Results are first obtained for benchmark problems involving steady injection-induced flow, and oscillatory and modulated …
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Partitioning Uncertainty for Non-Ergodic Probabilistic Seismic Hazard Analyses
… aleatoric variability associated with predicting pseudo-spectral accelerations. Third, two GMPEs were developed for active crustal earthquakes in Japan. The two GMPEs followed the ergodic and site-specific formulations, respectively. Finally, a comprehensive residual analysis was conducted to find …
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Modeling wind forcing in phase resolving simulation of nonlinear wind waves
… broadband wind waves based on the High Order Spectral (HOS) method (Dommermuth and Yue 1987). The original HOS method, which is a nonlinear pseudo-spectral numerical technique for phase resolving simulation of free regular waves, is extended to simulation of wind forced irregular broadband …
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Subgrid Scale Modeling for Large Eddy Simulation of Buoyant Turbulent Flows
… flow configurations is carried out using a pseudo-spectral method, which is free from numerical errors, and artifacts such as the effect of artificial boundary conditions. A well-validated and accurate DNS database is generated, and employed for a priori evaluation of various SGS models. The …
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