# Terry Ligocki

Terry J. Ligocki
Computer Systems Engineer
Phone: +1 510 486 6140
Fax: +1 510 486 6900

Terry has been a core developer of the Chombo library for numerically solving PDE using adaptive mesh refinement techniques since he joined the Applied Numerical Algorithms Group, ANAG, at LBNL in 2001.  He has focused on the embedded boundary aspects of the Chombo library.  Specifically, embedded boundary generation from implicitly defined volumes created using constructive solid geometry.  His research interests include computational geometry, finite volume numerical algorithms, and transforming complex algorithms for large scale computing.  He was a member of APDEC for SciDAC and SciDAC 2 and a member of FASTMath for SciDAC 3.

## Talks

• ICIAM 2003 (July 8, 2003) - Cartesian Grid Embedded Boundary Methods for Solving Applied PDEs (PDF)
• IPAM Talk (March 28, 2005) - Hyperbolic Conservation Laws and Visualization and Data Analysis In Chombo (PDF)
• IPDPS 2009 (May 28, 2009) - Scalability Challenges for Massively Parallel AMR Applications (PDF)

## Reports

### Brian Van Straalen, David Trebotich, Terry Ligocki, Daniel T. Graves, Phillip Colella, Michael Barad,"An Adaptive Cartesian Grid Embedded Boundary Method for the Incompressible Navier Stokes Equations in Complex Geometry",LBNL Report Number: LBNL-1003767,2012,LBNL LBNL Report Numb,

We present a second-order accurate projection method to solve the
incompressible Navier-Stokes equations on irregular domains in two
and three dimensions.  We use a finite-volume discretization
obtained from intersecting the irregular domain boundary with a
Cartesian grid.  We address the small-cell stability problem
associated with such methods by hybridizing a conservative
discretization of the advective terms with a stable, nonconservative
discretization at irregular control volumes, and redistributing the
difference to nearby cells.  Our projection is based upon a
finite-volume discretization of Poisson's equation.  We use a
second-order, $L^\infty$-stable algorithm to advance in time.  Block
structured local refinement is applied in space.  The resulting
method is second-order accurate in $L^1$ for smooth problems.  We
demonstrate the method on benchmark problems for flow past a
cylinder in 2D and a sphere in 3D as well as flows in 3D geometries
obtained from image data.