Simulation of incompressible viscous flows past a circular cylinder by hybrid FD scheme and meshless least square-based finite difference method

Ding, Hang; Chen, Shu; Yeo, K. S.; Xu, Dongsheng

doi:10.1016/j.cma.2003.11.002

Cited by 157 publications

(91 citation statements)

References 23 publications

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“…(5) is solved using the SOR method. First of all, each stationary (28,29) and oscillating cylinder (30) 0 . At the inflow boundary, uniform flow ( ) ( )…”

Section: Basic Equations and Numerical Methodsmentioning

confidence: 99%

Accelerated Motions of a Fish-Like Foil from Impulsive Starts to Terminal States

Ogata

Ogasawara

2012

JFST

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It is presented through numerical analysis that accelerated motions of a two-dimensional fish-like foil by fluid forces can be modeled from impulsive starts to terminal states. Time histories of drag coefficient and foil speed depend on a frequency and motion of a foil and amplitude of its caudal fin. Three models that take thrust, inertial drag and viscous drag into account for the time histories of foil speed and drag coefficient are suggested. It is indicated that the model using viscous drag is in good agreement with numerical solutions in various conditions for small Reynolds numbers. Thrust, drag and terminal velocity can be summarized by functions that are almost power laws of the foil frequency even for various wavy lateral oscillations of the midline of a foil.

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“…(5) is solved using the SOR method. First of all, each stationary (28,29) and oscillating cylinder (30) 0 . At the inflow boundary, uniform flow ( ) ( )…”

Section: Basic Equations and Numerical Methodsmentioning

confidence: 99%

Accelerated Motions of a Fish-Like Foil from Impulsive Starts to Terminal States

Ogata

Ogasawara

2012

JFST

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“…to equation system (21). In the case of Neumann boundary conditions, this subsystem can be used to impose a derivative boundary value at…”

Section: For a Segment [ J] With Interior And Boundary Pointsmentioning

confidence: 99%

“…In the second problem, it is well-known that the flow has a stable pattern with a fixed pair of symmetric vortices behind the cylinder at Re up to 40. Ding et al [21] presented a hybrid approach, which combines the conventional FDM and the meshfree least square-based finite difference (MLSFD) method for simulating the 2D steady and unsteady incompressible flows. In their works, the MLSFD method was adopted to deal with the spatial discretisation in the region with complex geometry and the conventional FDM was applied in the rest of the flow domain to take advantage of its high computational efficiency.…”

Section: Introductionmentioning

confidence: 99%

Local moving least square‐one‐dimensional integrated radial basis function networks technique for incompressible viscous flows

Ngo-Cong

Mai‐Duy

Karunasena

et al. 2012

Numerical Methods in Fluids

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This paper presents a local moving least square -one-dimensional integrated radial basis function networks (LMLS-1D-IRBFN) method for solving incompressible viscous flow problems using stream function-vorticity formulation. In this method, the partition of unity method is employed as a framework to incorporate the moving least square (MLS) and one-dimensional integrated radial basis function networks (1D-IRBFN) techniques. The major advantages of the proposed method include: (i) a banded sparse system matrix which helps reduce the computational cost; (ii) the Kronecker-δ property of the constructed shape function which helps impose the essential boundary condition in an exact manner; and (iii) high accuracy and fast convergence rate owing to the use of integration instead of conventional differentiation to construct the local RBF approximations. Several examples including two-dimensional Poisson problems, lid-driven cavity flow and flow past a circular cylinder are considered and the present results are compared with the exact solutions and numerical results from other methods in the literature to demonstrate the attractiveness of the proposed method.

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“…Results have been obtained for a range of actuation frequencies and applied voltages: f j ∈ [15,180] Hz and V rms ∈ [15,40] V. The results show an approximately linear behavior of the peak velocity with respect to the applied voltage, V rms . Furthermore, the highest peak velocity occurs at the lowest investigated frequency, f j = 15 Hz, and decreases with increasing actuation frequency.…”

Section: Performance Of Synthetic Jet Actuation Systemmentioning

confidence: 96%

“…For example, a grid refinement study by Cox et al [177] at Re D = 1000 (laminar flow) and Re D = 5 · 10 Reference Details Cox et al [177] compressible URANS (M = 0. [180] incompressible URANS (stream function-vorticity formulation), O ∆x 2 , ∆t 4 , hybrid conventional/mesh-free FD method, rectangular domain with farfield at 30D (downstream), 8D (upstream) and 16D (cross-stream) from center, steps/cycle based on stability of RK4 explicit time integration (turbulent flow) shows that the error in the computed Strouhal number on their standard grid with 197 × 97 points and the farfield boundary at 20D from the center is within 4% of the extrapolated value for an infinitely refined grid, whereas a finer grid 289 × 145 grid yields an error of 2%. If we assume that these values are also representative for Re D = 200, then an error margin of 3% to their result yields a Strouhal number of St = 0.192 ± 0.06.…”

Section: Time-dependent Flow Around Circular Cylindermentioning

confidence: 99%

On synthetic jet actuation for aerodynamic load control

Vries¹

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SummaryA major goal for the wind energy industry is the reduction of the cost of energy. This drives the design towards increasingly larger wind turbines. The technology of smart rotor control is expected to allow wind turbines to increase even further in size. Smart rotor control consists of a sequence of local load control mechanisms, distributed along the span of a wind turbine blade, which are operated individually based on local sensory information. This technology has the potential to reduce fatigue inducing variations in blade loads.Fatigue loads are induced by cyclic effects, such as wind shear, gravity and yaw misalignment, or by stochastic effects, such as turbulence in the upstream flow. Alleviation of the fatigue loads reduces the structural requirements of multiple components of a wind turbine, which allows for relatively lighter structures and less maintenance. It is expected that this will decrease the cost of energy, due to a combination of increased energy production and relatively lower capital and maintenance costs of a large but lighter wind turbine equipped with smart rotor control.The aerodynamic effect needed for smart rotor control is 'local pitch control', which aims for changes in the local aerodynamic characteristics, mainly the lift coefficient (c l ), over the range of angles of attack (α) in the linear c l (α)-regime. This aerodynamic effect can also be employed for other turbomachinery and in wing aerodynamics in the field of aeronautics. Potential options for local pitch control are trailing edge flaps, micro-tabs (small deployable Gurney flaps) and blade morphing. Active fluidic control close to the trailing edge by means of jets is an alternative option.In the present research, synthetic jets have been investigated as a potential option for local pitch control. Synthetic jets are generated by repeated ingestion and subsequent ejection of air, into and out of a cavity below the surface of the blade, respectively, through holes or slits in the surface of this blade. This oscillatory ejection/ingestion is caused by a vibrating wall inside the cavity, such as a piston or a piezoceramic composite diaphragm. The technology of synthetic jets can be used for boundary layer separation control, as well as pitch control.In the present thesis, a multi-purpose computational method has been developed for the simulation of unsteady compressible viscous flows. This method is, in principle, able to address the relevant characteristic flow effects associated with synthetic jet actuation. The computational method solves the unsteady Reynolds-averaged Navier-Stokes (URANS) equations for unsteady compressible viscous flow, together with the equation(s) of a linear eddy-viscosity turbulence model. The equations are discretized on unstructured computational grids, employing the Finite Volume method on cell-centered control volumes. The discretization is nominally of second order accuracy, both in space and time.iii An exception is the discretization of the convective flux in the equation(s) of the tur...

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Simulation of incompressible viscous flows past a circular cylinder by hybrid FD scheme and meshless least square-based finite difference method

Cited by 157 publications

References 23 publications

Accelerated Motions of a Fish-Like Foil from Impulsive Starts to Terminal States

Accelerated Motions of a Fish-Like Foil from Impulsive Starts to Terminal States

Local moving least square‐one‐dimensional integrated radial basis function networks technique for incompressible viscous flows

On synthetic jet actuation for aerodynamic load control

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