305 Implementation of Immersed-Boundary Method to CIP/Multi Moment Finite Volume Method

2007 ◽  
Vol 2007.20 (0) ◽  
pp. 587-588
Author(s):  
Keita MATSUMOTO ◽  
Feng XIAO
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.


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.


2014 ◽  
Vol 592-594 ◽  
pp. 1945-1949 ◽  
Author(s):  
Ranjith Maniyeri

Inspired by the propulsion of organisms in a viscous fluid, we develop a two-dimensional computational model to study the propulsive and fluid dynamic features of an organism modeled as an elastic filament in viscous fluid using immersed boundary (IB) finite volume method. The elastic filament is modeled using discrete number of IB points. The elastic forces are computed based on an elastic energy function. The Navier-Stokes equations governing the fluid flow are solved on a staggered Cartesian grid system using the fractional step based finite volume method. The computational model is validated by comparing the numerical simulation results pertinent to the swimming of an infinite with that of the existing analytical results. The interplay of propulsive and fluiddynamic features of the organism in the viscous fluid is well captured using the developed model.


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