A Vortex Immersed Boundary Method for Bluff Body Flows

Cottet, Georges-Henri; Gallizio, Federico; Magni, Adrien; Mortazavi, Iraj

doi:10.1115/fedsm-icnmm2010-30787

Cited by 7 publications

(6 citation statements)

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“…Numerical results are presented for vorticity isocontours in Figure 10. The vorticity isocontour patterns are in good agreement with the vortex immersed boundary method results of Cottet et al (2010) [35], although their results are not presented here. In Figure 11(a), it is seen that the so-called and phenomena observed experimentally by Bouard and Coutanceau (1980) are well captured by our numerical simulation.…”

Section: Unsteady Flow Past a Circularsupporting

confidence: 88%

Computation of Pressure Fields around a Two-Dimensional Circular Cylinder Using the Vortex-In-Cell and Penalization Methods

Lee

Suh

2014

Modelling and Simulation in Engineering

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The vorticity-velocity formulation of the Navier-Stokes equations allows purely kinematical problems to be decoupled from the pressure term, since the pressure is eliminated by applying the curl operator. The Vortex-In-Cell (VIC) method, which is based on the vorticity-velocity formulation, offers particle-mesh algorithms to numerically simulate flows past a solid body. The penalization method is used to enforce boundary conditions at a body surface with a decoupling between body boundaries and computational grids. Its main advantage is a highly efficient implementation for solid boundaries of arbitrary complexity on Cartesian grids. We present an efficient algorithm to numerically implement the vorticity-velocity-pressure formulation including a penalty term to simulate the pressure fields around a solid body. In vorticity-based methods, pressure field can be independently computed from the solution procedure for vorticity. This clearly simplifies the implementation and reduces the computational cost. Obtaining the pressure field at any fixed time represents the most challenging goal of this study. We validate the implementation by numerical simulations of an incompressible viscous flow around an impulsively started circular cylinder in a wide range of Reynolds numbers: Re=40, 550, 3000, and 9500.

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Section: Unsteady Flow Past a Circularsupporting

confidence: 88%

Computation of Pressure Fields around a Two-Dimensional Circular Cylinder Using the Vortex-In-Cell and Penalization Methods

Lee

Suh

2014

Modelling and Simulation in Engineering

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“…This hybrid vortex penalization method has already been successfully used to simulate high Reynolds flow regimes past bluff bodies [12,24].…”

Section: Vortex Penalization Methods In Vorticity Formulationmentioning

confidence: 98%

Passive Flow Control Around a Semi-Circular Cylinder Using Porous Coatings

Mimeau¹,

Cottet²,

Mortazavi³

2014

International Journal of Flow Control

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In this paper, the passive control of flow past a semi-circular cylinder is investigated. This control is achieved by adding a porous medium between the solid obstacle and the incompressible fluid in order to reduce drag forces and regularize the flow. A vortexpenalization method is chosen to easily model the flow in the different media. Several configurations of the porous layer are investigated and parametric studies are performed in order to determine the most efficient passive flow control devices. This control study can be considered as a first step to propose efficient strategies to regularize the flow around a side-view mirror. NOMENCLATUREC D drag coefficient D computational domain F, S fluid domain and solid domain F D drag force Re Reynolds number Z enstrophy d non-dimensional diameter h reference mesh size k intrinsic permeability l ref height of the obstacle u ref reference velocity u = (u,v) velocity field u s body rigid motion u¯mean velocity magnitude u ∞ free stream velocity Γ D computational domain boundaries Δt time step Φ porosity λ penalization parameter μ dynamic viscosity ν kinematic viscosity r density of the fluid τ porous layer thickness χ S characteristic function ω vorticity field INTRODUCTIONOn a ground vehicle, the outside mirrors, due to their spanwise position, indeed generate a nonnegligible wake which interferes with the flow past car sides. They are responsible of up to 10% of the total vehicle drag but they only represent 0.5% of the total projected surface, which accounts for a good motivation to perform flow control past these obstacles. This work is devoted to the control of flow past a two-dimensional semi-circular cylinder which can be considered as a simplified section of a sideview mirror. As it was shown in [1, 2], a flow past a square back obstacle is not dominated by longitudinal three-dimensional vortical structures, therefore a preliminary two-dimensional study can be useful to supply information and general trends for a further control study in three dimensions around a hemisphere. The aim is to use a control device easy to set up, low cost and allowing to keep the geometry unchanged. As active control devices can be hardly implemented in such a case, an efficient passive strategy seems to be a good alternative. A suitable solution has already been proposed by Bruneau and Mortazavi in [3][4][5][6][7]. It consists in adding a porous sheath on the obstacle surface in order to reduce the vorticity generation of the boundary layer. The presence of a porous medium at the solid-fluid interface indeed imposes a kind of mixed boundary condition intermediate between the noslip and the slip one on the solid boundary [8]. As a result, the shear forces are decreased and the flow dynamics is smoothed. Consequently, the problem we have to solve involves three different media, namely the solid obstacle, the porous layer and the fluid. An easy way to tackle it is to use the penalization method [9]. This method is based on a unique model, the Brinkman-Navier-Stokes equations, which ...

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“…Vortex methods (see [18], [22] and [35]) and penalization methods (see [1] and [9]) have been separately used to compute incompressible high Reynolds number flows around obstacles. In this section, a novel hybrid particle-penalization technique is proposed to achieve efficient computations of bluff-body flows designing a more efficient technique that covers the advantages of both approaches [17]. In this approach, the vortex method is used to approximate the penalized Vorticity Transport Equations (VTE).…”

Section: Vortex Penalization Methodsmentioning

confidence: 99%

Immersed boundary methods for the numerical simulation of incompressible aerodynamics and fluid-structure interactions

James¹,

Maitre²,

Mortazavi³

2013

Ann. math. Blaise Pascal

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In this work three branches of Immersed Boundary Methods (IBM) are described and validated for incompressible aerodynamics and fluid-structure interactions. These three approaches are: Cut Cell method, Vortex-Penalization method and Forcing method. Two first techniques are validated for external bluff-body flows and the last one is used for fluid-structure interactions. The paper confirms the ability of this family of numerical schemes for accurate and robust simulation of incompressible flows. Méthodes de fontière immergée pour la simulation numérique en aérodynamique incompressible et interactions fluide-structure. Résumé. Dans ce travail, trois méthodes de frontière immergée sont dcrites et validées pour la simulation numérique en aérodynamique incompressible et interactions fluide-structure. Ces trois approches sont : une méthode Cut Cell, une méthode Vortex-Penalisation method et une méthode de forçage. Les deux premières techniques sont valides pour lesécoulements autour d'obstacle et la troisième est utilisée pour le calcul d'interactions fluide-structure. Ce papier confirme la capacit de cette famille de schémas numériques pour simuler lesécoulements incompressibles de manière précise et robuste.

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A Vortex Immersed Boundary Method for Bluff Body Flows

Cited by 7 publications

References 0 publications

Computation of Pressure Fields around a Two-Dimensional Circular Cylinder Using the Vortex-In-Cell and Penalization Methods

Computation of Pressure Fields around a Two-Dimensional Circular Cylinder Using the Vortex-In-Cell and Penalization Methods

Passive Flow Control Around a Semi-Circular Cylinder Using Porous Coatings

Immersed boundary methods for the numerical simulation of incompressible aerodynamics and fluid-structure interactions

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