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109
A Finite Element Approach to the Immersed Boundary Method
, 2004
"... The immersed boundary method was introduced by Peskin in [31] to study the blood flow in the heart and further applied to many situations where a fluid interacts with an elastic structure. The basic idea is to consider the structure as a part of the fluid where additional forces are applied and addi ..."
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The immersed boundary method was introduced by Peskin in [31] to study the blood flow in the heart and further applied to many situations where a fluid interacts with an elastic structure. The basic idea is to consider the structure as a part of the fluid where additional forces are applied and additional mass is localized. The forces exerted by the structure on the fluid are taken into account as a source term in the Navier-Stokes equations and are mathematically described as a Dirac delta function lying along the immersed structure. In this paper we first review on various ways of modeling the elastic forces in different physical situations. Then we focus on the discretization of the immersed boundary method by means of finite elements which can handle the Dirac delta function variationally avoiding the introduction of its regularization. Practical computational aspects are described and some preliminary numerical experiment in two dimensions are reported.
Simulations of the whirling instability by the immersed boundary method
- SIAM J. Sci. Comput
, 2004
"... Abstract. When an elastic filament spins in a viscous incompressible fluid it may undergo a whirling instability, as studied asymptotically by Wolgemuth, Powers, and Goldstein [Phys. Rev. Lett., 84 (2000), pp. 16–23]. We use the immersed boundary (IB) method to study the interaction between the elas ..."
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Abstract. When an elastic filament spins in a viscous incompressible fluid it may undergo a whirling instability, as studied asymptotically by Wolgemuth, Powers, and Goldstein [Phys. Rev. Lett., 84 (2000), pp. 16–23]. We use the immersed boundary (IB) method to study the interaction between the elastic filament and the surrounding viscous fluid as governed by the incompressible Navier–Stokes equations. This allows the study of the whirling motion when the shape of the filament is very different from the unperturbed straight state.
Fluid flow in collapsible elastic tubes: A three-dimensional numerical model
- New York J. Math
"... Abstract. A three-dimensional computer model has been developed to simulate fluid flow through a collapsible tube. The model is based on the immersed boundary method, which is designed to handle a flexible elastic boundary immersed in fluid. This internal boundary is both affected by and has an effe ..."
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Abstract. A three-dimensional computer model has been developed to simulate fluid flow through a collapsible tube. The model is based on the immersed boundary method, which is designed to handle a flexible elastic boundary immersed in fluid. This internal boundary is both affected by and has an effect on the motion of the fluid. The setup for collapsible tube simulation involves a fiber-wound elastic tube subjected to an upstream pressure, a downstream pressure, and an external pressure. Partial collapse is observed when the external pressure exceeds the downstream pressure but is less than the upstream pressure. The geometry of the transiently collapsing tube is observed. Collapse is generally localized near the downstream end of the tube, however, under certain conditions, it is also possible for collapse to occur at multiple discrete locations separated by regions of open tubing.
A cartesian grid method with transient anisotropic adaption
- Journal of Computational Physics
"... A Cartesian grid method with solution-adaptive anisotropic refinement and coars-ening is developed for simulating time-dependent incompressible flows. The Carte-sian grid cells and faces are managed using an unstructured data approach, and al-gorithms are described for the time-accurate transient an ..."
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Cited by 17 (2 self)
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A Cartesian grid method with solution-adaptive anisotropic refinement and coars-ening is developed for simulating time-dependent incompressible flows. The Carte-sian grid cells and faces are managed using an unstructured data approach, and al-gorithms are described for the time-accurate transient anisotropic refinement and coarsening of the cells. The governing equations are discretized using a collo-cated, cell-centered arrangement of velocity and pressure, and advanced in time using the fractional step method. Significant savings in the memory requirement of the method can be realized by advancing the velocity field using a novel ap-proximate factorization technique, although an iterative technique is also presented. The pressure Poisson equation is solved using additive correction multigrid, and an efficient coarse grid selection algorithm is presented. Finally, the Cartesian cell geometry allows the development of relatively simple analytic expressions for the optimal cell dimensions based on limiting the velocity interpolation error. The over-all method is validated by solving several benchmark flows, including the 2D and 3D lid-driven cavity flows, and the 2D flow around a circular cylinder. In this lat-ter case, an immersed boundary method is used to handle the embedded cylinder
Removing the Stiffness of Elastic Force from the Immersed Boundary Method for the 2D Stokes Equations
, 2008
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An Efficient Semi-Implicit Immersed Boundary Method for the Navier-Stokes Equations
, 2008
"... The Immersed Boundary method is one of the most useful computational methods in studying fluid structure interaction. On the other hand, the Immersed Boundary method is also known to require small time steps to maintain stability when solved with an explicit method. Many implicit or approximately im ..."
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Cited by 13 (0 self)
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The Immersed Boundary method is one of the most useful computational methods in studying fluid structure interaction. On the other hand, the Immersed Boundary method is also known to require small time steps to maintain stability when solved with an explicit method. Many implicit or approximately implicit methods have been proposed in the literature to remove this severe time step stability constraint, but none of them give satisfactory performance. In this paper, we propose an efficient semiimplicit scheme to remove this stiffness from the Immersed Boundary method for the Navier-Stokes equations. The construction of our semi-implicit scheme consists of two steps. First, we obtain a semi-implicit discretization which is proved to be unconditionally stable. This unconditionally stable semi-implicit scheme is still quite expensive to implement in practice. Next, we apply the Small Scale Decomposition to the unconditionally stable semi-implicit scheme to construct our efficient semi-implicit scheme. Unlike other implicit or semi-implicit schemes proposed in the literature, our semi-implicit scheme can be solved explicitly in the spectral space. Thus the computational cost of our semi-implicit schemes is comparable to that of an explicit scheme. Our extensive numerical experiments show that our semi-implicit scheme has much better stability property than an explicit scheme. This offers a substantial computational saving in using the Immersed Boundary method.
A new high-order immersed interface method for solving elliptic equations with imbedded interface of discontinuity
- J. Comput. Phys
, 2007
"... Abstract This paper presents a new high-order immersed interface method for elliptic equations with imbedded interface of discontinuity. Compared with the original second-order immersed interface method of [R.J. LeVeque, Z. Li. The immersed interface method for elliptic equations with discontinuous ..."
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Abstract This paper presents a new high-order immersed interface method for elliptic equations with imbedded interface of discontinuity. Compared with the original second-order immersed interface method of [R.J. LeVeque, Z. Li. The immersed interface method for elliptic equations with discontinuous coefficients and singular sources. SIAM J. Numer. Anal. 31 (1994) 1001-25], the new method achieves arbitrarily high-order accuracy for derivatives at an irregular grid point by imposing only two physical jump conditions together with a wider set of grid stencils. The new interface difference formulas are expressed in a general explicit form so that they can be applied to different multi-dimensional problems without any modification. The new interface algorithms of up to O(h 4 ) accuracy have been derived and tested on several one and twodimensional elliptic equations with imbedded interface. Compared to the standard second-order immersed interface method, the test results show that the new fourth-order immersed interface method leads to a significant improvement in accuracy of the numerical solutions. The proposed method has potential advantages in the application to two-phase flow because of its high-order accuracy and simplicity in applications.
Systematic derivation of jump conditions for the immersed interface method in three-dimensional flow simulation
- SIAM J. Sci. Comput
"... Abstract. In this paper, we systematically derive jump conditions for the immersed interface ..."
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Abstract. In this paper, we systematically derive jump conditions for the immersed interface
Electricallogic simulation
- In International Conference on Computer-Aided Design
, 1984
"... the dynamics of inextensible vesicles by the penalty immersed boundary method ..."
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the dynamics of inextensible vesicles by the penalty immersed boundary method
Distributed immersed boundary simulation in Titanium
- SIAM Journal of Scientific Computing
, 2006
"... Abstract. The immersed boundary method is a general technique for modeling elastic boundaries immersed within a viscous, incompressible fluid. The method has been applied to several biological and engineering systems, including large scale models of the heart and cochlea. These simulations have the ..."
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Cited by 9 (5 self)
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Abstract. The immersed boundary method is a general technique for modeling elastic boundaries immersed within a viscous, incompressible fluid. The method has been applied to several biological and engineering systems, including large scale models of the heart and cochlea. These simulations have the potential to improve our basic understanding of the biological systems they model and aid in the development of surgical treatments and prosthetic devices. Despite the popularity of the immersed boundary method and the desire to scale the problems to accurately capture the details of the physical systems, parallelization for large scale distributed memory machine has proven challenging. The primary reason is a classic locality and load balance tradeoff that arises in distributing the immersed boundary data structure across processors. In this paper we describe a parallelized algorithm for the immersed boundary method that is designed for scalability on distributed memory multiprocessors and clusters of SMPs. It is implemented using the Titanium language, a Java-based high performance scientific computing. Our software package, called IB, takes advantage of the object-oriented features of Titanium to provide a framework for simulating immersed boundaries that separates the generic immersed boundary method code from the specific application features that define the immersed boundary structure and the forces that arise from those structures. Our results demonstrate the scalability of our design and the feasibility of large scale immersed boundary computations with the IB package. 1.