Numerical Investigation of Vortex Shedding Modes of Flow past Two Circular Cylinders in Side-by-Side Using Immersed Boundary Method

2013 ◽  
Vol 275-277 ◽  
pp. 482-485
Author(s):  
Li Wei Song ◽  
Song Ping Wu
Keyword(s):  
Vortex Shedding ◽  
Immersed Boundary Method ◽  
Stokes Equations ◽  
Circular Cylinders ◽  
Immersed Boundary ◽  
Step Method ◽  
Fractional Step Method ◽  
Flow Past ◽  
Boundary Method ◽  
Vortex Shedding Modes

The vortex shedding modes of flow past two circular cylinders in side-by-side arrangement are investigated numerically in this paper. The simulations are carried out using a ghost cell immersed boundary method which imposes the boundary condition through reconstruction of the local velocity field near the immersed boundary. The two-dimensional unsteady incompressible Navier-Stokes equations are solved using an implicit fractional step method based on cell-center, collocated arrangement of the primary variables. Vorticity contours of the flow around the cylinders and force time histories are presented. Anti-phase and in-phase vortex shedding modes were found to exist in the flow simulation. These results of simulations were in agreement with phenomena observed in experiment and numerical results of previous researchers.

Ghost Cell Immersed Boundary Method for Simulating Flow over Two Circular Cylinders in Tandem Arrangement

2013 ◽  
Vol 275-277 ◽  
pp. 478-481
Author(s):  
Li Wei Song ◽  
Song Ping Wu
Keyword(s):  
Immersed Boundary Method ◽  
Stokes Equations ◽  
Circular Cylinders ◽  
Navier Stokes ◽  
Immersed Boundary ◽  
Ghost Cell ◽  
Step Method ◽  
Fractional Step Method ◽  
Tandem Arrangement ◽  
Boundary Method

In this work, a ghost cell immersed boundary method is applied to the numerical simulation of a uniform flows over a circular cylinder and two circular cylinders in tandem arrangement. The Navier-Stokes equations are solved using an implicit fractional step method employed on collocated arrangement variables. Immersed boundary method permit the use of structured Cartesian meshes to simulate flows involving complex boundaries. The shedding of vortices and flow interference between two circular cylinders in tandem arrangement are investigated numerically. The calculations are validated against the experimental and numerical results obtained by other researchers to prove the accuracy and effectiveness.

scholarly journals Immersed Boundary Method Application as a Way to Deal with the Three-Dimensional Sudden Contraction

Computation ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 50
Author(s):  
Jonatas Borges ◽  
Marcos Lourenço ◽  
Elie Padilla ◽  
Christopher Micallef
Keyword(s):  
Immersed Boundary Method ◽  
Stokes Equations ◽  
Computational Cost ◽  
Three Dimensional ◽  
Immersed Boundary ◽  
Fractional Step Method ◽  
Central Difference ◽  
Boundary Method ◽  
Contraction Ratio ◽  
Sudden Contraction

The immersed boundary method has attracted considerable interest in the last few years. The method is a computational cheap alternative to represent the boundaries of a geometrically complex body, while using a cartesian mesh, by adding a force term in the momentum equation. The advantage of this is that bodies of any arbitrary shape can be added without grid restructuring, a procedure which is often time-consuming. Furthermore, multiple bodies may be simulated, and relative motion of those bodies may be accomplished at reasonable computational cost. The numerical platform in development has a parallel distributed-memory implementation to solve the Navier-Stokes equations. The Finite Volume Method is used in the spatial discretization where the diffusive terms are approximated by the central difference method. The temporal discretization is accomplished using the Adams-Bashforth method. Both temporal and spatial discretizations are second-order accurate. The Velocity-pressure coupling is done using the fractional-step method of two steps. The present work applies the immersed boundary method to simulate a Newtonian laminar flow through a three-dimensional sudden contraction. Results are compared to published literature. Flow patterns upstream and downstream of the contraction region are analysed at various Reynolds number in the range 44 ≤ R e D ≤ 993 for the large tube and 87 ≤ R e D ≤ 1956 for the small tube, considerating a contraction ratio of β = 1 . 97 . Comparison between numerical and experimental velocity profiles has shown good agreement.

Immersed Boundary Method for Simulation of Oscillatory Flow Past a Submerged Cylinder Near Above a Horizontal Bed

2014 ◽  
Author(s):  
Efstratios N. Fonias ◽  
Athanassios A. Dimas
Keyword(s):  
Reynolds Number ◽  
Immersed Boundary Method ◽  
Oscillatory Flow ◽  
Stokes Equations ◽  
Immersed Boundary ◽  
Critical Range ◽  
Flow Past ◽  
Boundary Method ◽  
Flow Past A Cylinder ◽  
Submerged Cylinder

In the present work, the oscillatory flow past a submerged cylinder near above a horizontal bed is simulated by a Navier-Stokes equations solver. The boundary conditions, i.e., the no-slip condition on solid boundaries are imposed with the immersed boundary method. A Cartesian grid with variable size is used for the spatial discretization, and a time-splitting scheme is used for the temporal discretization. The numerical method was validated simulating the unidirectional flow past a cylinder at Reynolds number ReD = 300. For the oscillatory flow past a cylinder of diameter D at a distance G above a horizontal bed, all variables were rendered dimensionless using the maximum velocity, Uo, and the amplitude of the orbital motion, αo, of the oscillatory flow. Several tests with differing values of αo/D and G/D were considered, for Reynolds number Reα = 5,000 and Keulegan–Carpenter numbers in the range from 6.28 to 62.8. Results show that the critical range for the suppression of vortex shedding at the lower side of the cylinder is G/αo<0.01, while the critical range for the generation of vorticity uplift from the bed boundary layer is G/αo<1.0. Also, as G/D decreases, both the amplitude of the drag force and the bias towards positive values of the lift force increase.

FINITE ELEMENT APPROACH TO IMMERSED BOUNDARY METHOD WITH DIFFERENT FLUID AND SOLID DENSITIES

2011 ◽  
Vol 21 (12) ◽  
pp. 2523-2550 ◽  
Author(s):  
DANIELE BOFFI ◽  
NICOLA CAVALLINI ◽  
LUCIA GASTALDI
Keyword(s):  
Finite Element ◽  
Immersed Boundary Method ◽  
Stokes Equations ◽  
Numerical Procedure ◽  
Biological Tissues ◽  
Immersed Boundary ◽  
Fluid Structure ◽  
Finite Element Approach ◽  
Boundary Method ◽  
Element Approach

The Immersed Boundary Method (IBM) has been designed by Peskin for the modeling and the numerical approximation of fluid-structure interaction problems, where flexible structures are immersed in a fluid. In this approach, the Navier–Stokes equations are considered everywhere and the presence of the structure is taken into account by means of a source term which depends on the unknown position of the structure. These equations are coupled with the condition that the structure moves at the same velocity of the underlying fluid. Recently, a finite element version of the IBM has been developed, which offers interesting features for both the analysis of the problem under consideration and the robustness and flexibility of the numerical scheme. Initially, we considered structure and fluid with the same density, as it often happens when dealing with biological tissues. Here we study the case of a structure which can have a density higher than that of the fluid. The higher density of the structure is taken into account as an excess of Lagrangian mass located along the structure, and can be dealt with in a variational way in the finite element approach. The numerical procedure to compute the solution is based on a semi-implicit scheme. In fluid-structure simulations, nonimplicit schemes often produce instabilities when the density of the structure is close to that of the fluid. This is not the case for the IBM approach. In fact, we show that the scheme enjoys the same stability properties as in the case of equal densities.

scholarly journals A Stress Mapping Immersed Boundary Method for Viscous Flows

2021 ◽  
Vol 87 (3) ◽  
pp. 1-20
Author(s):  
Karim M. Ali ◽  
Mohamed Madbouli ◽  
Hany M. Hamouda ◽  
Amr Guaily
Keyword(s):  
Immersed Boundary Method ◽  
Stokes Equations ◽  
Cross Flow ◽  
Navier Stokes ◽  
Immersed Boundary ◽  
Element Formulation ◽  
Navier Stokes Equations ◽  
Boundary Method ◽  
Background Grid ◽  
Dimensional Simulation

This work introduces an immersed boundary method for two-dimensional simulation of incompressible Navier-Stokes equations. The method uses flow field mapping on the immersed boundary and performs a contour integration to calculate immersed boundary forces. This takes into account the relative location of the immersed boundary inside the background grid elements by using inverse distance weights, and also considers the curvature of the immersed boundary edges. The governing equations of the fluid mechanics are solved using a Galerkin-Least squares finite element formulation. The model is validated against a stationary and a vertically oscillating circular cylinder in a cross flow. The results of the model show acceptable accuracy when compared to experimental and numerical results.

An Immersed Boundary Method for Compressible Flows with Complex Boundaries

2013 ◽  
Vol 477-478 ◽  
pp. 281-284
Author(s):  
Jie Yang ◽  
Song Ping Wu
Keyword(s):  
Immersed Boundary Method ◽  
Compressible Flows ◽  
Stokes Equations ◽  
Splitting Method ◽  
Linear Interpolation ◽  
High Order Accuracy ◽  
Navier Stokes ◽  
Immersed Boundary ◽  
Central Difference ◽  
Boundary Method

An immersed boundary method based on the ghost-cell approach is presented in this paper. The compressible Navier-Stokes equations are discretized using a flux-splitting method for inviscid fluxes and second-order central-difference for the viscous components. High-order accuracy is achieved by using weighted essentially non-oscillatory (WENO) and Runge-Kutta schemes. Boundary conditions are reconstructed by a serial of linear interpolation and inverse distance weighting interpolation of flow variables in fluid domain. Two classic flow problems (flow over a circular cylinder, and a NACA 0012 airfoil) are simulated using the present immersed boundary method, and the predictions show good agreement with previous computational results.

COMPUTATIONAL SIMULATION OF FLUID FLOW OVER A TRIANGULAR STEP USING IMMERSED BOUNDARY METHOD

2013 ◽  
Vol 10 (04) ◽  
pp. 1350016 ◽  
Author(s):  
C. A. SALEEL ◽  
A. SHAIJA ◽  
S. JAYARAJ
Keyword(s):  
Fluid Flow ◽  
Immersed Boundary Method ◽  
Reynolds Numbers ◽  
Stream Line ◽  
Immersed Boundary ◽  
Complex Geometries ◽  
Backward Facing Step ◽  
Fractional Step Method ◽  
Boundary Method ◽  
Fluid Solid Interaction

Handling of complex geometries with fluid–solid interaction has been one of the exigent issues in computational fluid dynamics (CFD) because most engineering problems have complex geometries with fluid–solid interaction for the purpose. Two different approaches have been developed for the same hitherto: (i) The unstructured grid method and (ii) the immersed boundary method (IBM). This paper details the IBM for the numerical investigation of two-dimensional laminar flow over a backward facing step and various geometrically configured triangular steps in hydro-dynamically developing regions (entrance region) as well in the hydro-dynamically developed regions through a channel at different Reynolds numbers. The present numerical method is rooted in a finite volume approach on a staggered grid in concert with a fractional step method. Geometrical obstructions are treated as an immersed boundary (IB), both momentum forcing and mass source terms are applied on the obstruction to satisfy the no-slip boundary condition and also to satisfy the continuity for the mesh containing the immersed boundary. Initially, numerically obtained velocity profiles and stream line plots for fluid flow over backward facing step is depicted to show its excellent agreement with the published results in various literatures. There after profiles and plots in the channel with triangular steps are also being unveiled with in depth elucidation. Results are presented for different Reynolds numbers.

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