[Crib-list] Speaker: KRZYSZTOF J. FIDKOWSKI (MIT) -- Computational Research in Boston Seminar -- Friday, November 2, 2007 -- 12:30 PM -Room 32-124 (Stata Center)

[Shirley Entzminger]

T O D A Y . . .

 			COMPUTATIONAL RESEARCH in BOSTON SEMINAR

NOTE:  New location.
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Date:		FRIDAY, NOVEMBER 2, 2007
Time:		12:30 PM
Location:	Building 32, Room 124 (Stata Center)

(Pizza and beverages will be provided at 12:15 PM outside Room 32-124.)



Title:		TOWARDS AUTOMATED MESH ADAPTATION USING SIMPLEX CUT CELLS

Speaker:	KRZYSZTOF J. FIDKOWSKI
 		(Massachusetts Institute of Technology)


ABSTRACT:

Even with today's computing resources, high-fidelity Computational Fluid 
Dynamics (CFD) remains a time-consuming and user-intensive process.  Error 
estimation and mesh generation/adaptation in industry applications are largely 
performed by experienced practitioners.  This lack of automation prevents 
widespread use of CFD in design and optimization, especially for complex 
configurations.

Methods for rigorous error estimation exist, but have yet to be applied on a 
large scale to complex three-dimensional cases.  The bottleneck is primarily a 
lack of automated metric-driven meshing.  Currently, the generation of 
boundary-conforming meshes with anisotropic boundary layers requires heavy user 
involvement.  One solution is the Cartesian cut-cell method, in which the 
computational mesh is obtained by cutting the geometry out of a lattice-bound 
structured mesh.  However, current finite volume Cartesian methods are at best 
second-order accurate and require impractically high mesh counts for problems 
exhibiting anisotropy, such as thin boundary layers.

This talk presents a simplex cut cell method, in which the computational mesh 
is obtained by cutting the geometry out of a triangular or tetrahedral 
background mesh that does not need to conform to the geometry boundary.  Use of 
triangles and tetrahedral allows the mesh to be stretched in arbitrary 
directions to efficiently resolve anisotropic flow features.  The target 
application for this work is the discontinuous Galerkin (DG) finite element 
discretization of the compressible Navier-Stokes equations in both two and 
three dimensions.  Accuracy of cut-cell solutions is demonstrated by comparison 
to boundary-conforming solutions when available.  Adaptive results for 
anisotropic problems in two dimensions and isotropic problems in three 
dimensions indicate that automated output-driven adaptation is possible with 
cut cells.  Finally, a possible extension of simplex cut cells for dealing with 
curved anisotropic features is discussed.

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Massachusetts Institute of Technology
Cambridge, MA  02139


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