109
reads

Khoon Seng Yeo

2013-11-13
09:10:00 - 10:20:00

308 , Mathematics Research Center Building (ori. New Math. Bldg.)

In recent years, a good deal of CFD research has gone into the development of schemes for dealing with moving and deforming boundary problems. These have been motivated by applications to biological or bio-medical related flows, flows with interfaces as in free surface flow and multi-phase flows. The main approaches may be broadly divided into two groups: body conformal and non-body conformal grids. The former comprises the well-known Finite Volume, Finite Element, and Composite/Chimera grid methods. Non-body conformal grids usually employ a background grid, which is frequently Cartesian: interface may be explicitly tracked by a phase function (Volume-of-Fluid methods) or a gradient function (Level Set methods); or interface may be defined by a diffused interpolation scheme (such as the Immersed Boundary Methods and its many variants). In this workshop I will describe a body-conformal CFD scheme that is based on a hybrid Cartesian-meshfree grid. In this scheme, the boundary/body and its near field are discretized by meshfree nodes and set against a background Cartesian grid frame. The scheme provides accurate boundary definition and good geometric flexibility. Discretization at non-Cartesian nodes is carried by a generalized finite difference (GFD) scheme, while discretization on Cartesian nodes (which form the bulk of computational nodes) follows the highly efficient standard central FD. The meshfree nodes convect with the motion and deformation of the boundary/body; the latter are incorporated into the fluid dynamics via an ALE procedure. Dynamic interaction of fluid and body leading to motion is solved by an implicit iterative procedure. The scheme is well tailored for external type deforming boundary driven flows such as those that arise in animal propulsion. Applications have been made to the study of fish swimming and flapping wing flight. A high-order generalized difference scheme with highly compact support was also recently developed.

For material related to this talk, click here.