[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]

 			COMPUTATIONAL RESEARCH in BOSTON SEMINAR

NOTE:  New location.
-------------------

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.

******************************************************************************
Massachusetts Institute of Technology
Cambridge, MA  02139


http://www-math.mit.edu/crib

For information on CRiB, contact:

Alan Edelman:  edelman at math.mit.edu
Steven G. Johnson:  stevenj at math.mit.edu
Jeremy Kepner:  kepner at ll.mit.edu
Patrick Dreher:  dreher at mit.edu