scholarly journals An Unstructured Finite Volume Method for Incompressible Flows With Complex Immersed Boundaries

Author(s):  
Lin Sun ◽  
Sanjay R. Mathur ◽  
Jayathi Y. Murthy

A numerical method is developed for solving the 3D, unsteady, incompressible flows with immersed moving solids of arbitrary geometrical complexity. A co-located (non-staggered) finite volume method is employed to solve the Navier-Stokes governing equations for flow region using arbitrary convex polyhedral meshes. The solid region is represented by a set of material points with known position and velocity. Faces in the flow region located in the immediate vicinity of the solid body are marked as immersed boundary (IB) faces. At every instant in time, the influence of the body on the flow is accounted for by reconstructing implicitly the velocity the IB faces from a stencil of fluid cells and solid material points. Specific numerical issues related to the non-staggered formulation are addressed, including the specification of face mass fluxes, and corrections to the continuity equation to ensure overall mass balance. Incorporation of this immersed boundary technique within the framework of the SIMPLE algorithm is described. Canonical test cases of laminar flow around stationary and moving spheres and cylinders are used to verify the implementation. Mesh convergence tests are carried out. The simulation results are shown to agree well with experiments for the case of micro-cantilevers vibrating in a viscous fluid.

1992 ◽  
Vol 114 (4) ◽  
pp. 496-503 ◽  
Author(s):  
S. Majumdar ◽  
W. Rodi ◽  
J. Zhu

A finite-volume method is presented for calculating incompressible 3-D flows with curved irregular boundaries. The method employs structured nonorthogonal grids, cell-centered variable arrangement, and Cartesian velocity components. A special interpolation procedure for evaluating the mass fluxes at the cell-faces is used to avoid the nonphysical oscillation of flow variables usually encountered with the cell-centered arrangement. The SIMPLE algorithm is used to handle the pressure-velocity coupling. A recently proposed low diffusive and bounded scheme is introduced to approximate the convection terms in the transport equations. The computer code and the relevant data structure are so organized that most of the code except the implicit linear solver used is fully vectorizable so as to exploit the potential of modern vector computers. The capabilities of the numerical procedure are demonstrated by application to a few internal and external three-dimensional laminar flows. In all cases the CPU-time on a grid with typically 28,000 grid nodes was below half a minute.


2013 ◽  
Vol 2013.26 (0) ◽  
pp. _303-1_-_303-2_
Author(s):  
Takeshi INOMOTO ◽  
Kenichi MATSUNO ◽  
Masashi YAMAKAWA

Author(s):  
Yanbo Huang ◽  
Shanshan Li ◽  
Zhenhai Pan

Abstract Fluid-structure interaction (FSI) is an important fundamental problem with wide scientific and engineering applications. The immersed boundary method has proved to be an effective way to model the interaction between a moving solid and its surrounding fluid. In this study, a novel modeling approach based on the coupled immersed-boundary and finite-volume method is proposed to simulate fluid-structure interaction problems. With this approach, the whole computational domain is treated as fluid and discretized by only one set of Eulerian grids. The computational domain is divided into solid parts and fluid parts. A goal velocity is locally determined in each cell inside the solid part. At the same time, the hydrodynamic force exerted on the solid structure is calculated by integrating along the faces between the solid cells and fluid cells. In this way, the interaction between the solid and fluid is solved explicitly and the costly information transfer between Lagranian grids and Eulerian grids is avoided. The interface is sharply restricted into one single grid width throughout the iterations. The proposed modeling approach is validated by conducting several classic numerical experiments, including flow past static and freely rotatable square cylinders, and sedimentation of an ellipsoid in finite space. Throughout the three numerical experiments, satisfying agreements with literatures have been obtained, which demonstrate that the proposed modeling approach is accurate and robust for simulating FSI problems.


2006 ◽  
Vol 33 (1) ◽  
pp. 41-48 ◽  
Author(s):  
M Gunal ◽  
A Guven

The basic goal of this study is to present a numerical simulation model for turbulent water flow issued on frozen scoured beds. The model uses a finite volume method to solve the equations of motion and transport equations for two dimensions on a transformed rectangular domain using boundary-fitted coordinates. The internal characteristics of the mean flow of submerged horizontal jets including surface profiles on frozen scoured beds are computed by a two-dimensional k–ε turbulence model. Computations are carried out at different frozen-scoured bed profiles. A staggered grid system is adapted for variable arrangements to avoid the well-known checkerboard oscillations in pressure and velocity. The SIMPLE algorithm is adapted for the computation. No experimental studies were performed during this investigation. The diffusion characteristics of the submerged jet, growth of boundary layer thickness, velocity distribution within the boundary layer, and shear stress at the scour are investigated and compared with the results of others. Key words: boundary-fitted coordinates, local scour, k–ε model, finite volume method, horizontal jets, submerged jets.


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