When an elastic filament spins in a viscous incompressible fluid it may undergo a whirling instability, as studied asymptotically by Wolgemuth, Powers, Goldstein [1]. 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 and to determine the nature of the bifurcat...

Introduction Conclusions References Tables Figures ◭ ◮ ◭ ◮ Back Close Full Screen / Esc Abstract Introduction Conclusions References Tables Figures ◭ ◮ ◭ ◮ Back Close Full Screen / Esc Abstract This study is aimed at clarifying the relative importance of the specific character of the nuclei and of the duration of supercooling in heterogeneous freezing nucleation by immersed impurities. Laborato...

A hybrid immersed boundary-lattice Boltzmann method IB-LBM is presented in this work to simulate the thermal flow problems. In current approach, the flow field is resolved by using our recently developed boundary condition-enforced IB-LBM Wu and Shu, 2009 . The nonslip boundary condition on the solid boundary is enforced in simulation. At the same time, to capture the temperature development, t...

In this paper, we analyze the convergence of the immersed boundary (IB) method as applied to a static Stokes flow problem. Using estimates obtained in [5], we consider a problem in which a d-dimensional structure is immersed in n-dimension, and prove error estimates for both the pressure and the velocity field in the Lp(1 ≤ p ≤ ∞) norm. One interesting consequence of our analysis is that the as...

Explicit time stepping schemes for the immersed boundary method require very small time steps in order to maintain stability. Solving the equations that arise from an implicit discretization is difficult. Recently, several different approaches have been proposed, but a complete understanding of this problem is still emerging. A multigrid method is developed and explored for solving the equation...

Abstract   The present paper is devoted to implementation of the immersed boundary technique into the Fourier pseudo-spectral solution of the vorticity-velocity formulation of the two-dimensional incompressible Navier-Stokes equations. The immersed boundary conditions are implemented via direct modification of the convection and diffusion terms, and therefore, in contrast to some other similar ...

We consider the immersed boundary problem in which the boundary separates two very viscous fluids with differing viscosities. The moving elastic boundary may exert a force on the local fluid. The model solution is obtained using the immersed interface method, which computes second-order accurate approximations by incorporating known jumps in the solution or its derivatives into a finite differe...

We present an immersed boundary method based on volume penalization, with which pulsatile flow in a model cerebral aneurysm is simulated. The model aneurysm consists of a curved vessel merged with a spherical cavity. The dominant vortical structures arising in the time-dependent flow are discussed and the evolution of the maximal shear stress in the aneurysm is analyzed. We approximate flow pro...

Many immersed boundary methods solve for surface stresses that impose the velocity boundary conditions on an immersed body. These surface stresses may contain spurious oscillations that make them ill-suited for representing the physical surface stresses on the body. Moreover, these inaccurate stresses often lead to unphysical oscillations in the history of integrated surface forces such as the ...

The cochlea or inner ear has a remarkable ability to amplify sound signals. This is understood to derive at least in part from some active process that magnifies vibrations of the basilar membrane (BM) and the cochlear partition in which it is embedded, to the extent that it overcomes the effect of viscous damping from the surrounding cochlear fluid. Many authors have associated this amplificat...