# Brian Van Straalen

Brian Van Straalen
Computer Systems Engineer
Phone: +1 510 486 4976
Fax: +1 510 486 6900

Brian Van Straalen received his BASc Mechanical Engineering in 1993 and MMath in Applied Mathematics in 1995 from University of Waterloo.  He has been working in the area of scientific computing since he was an undergraduate. He worked with Advanced Scientific Computing Ltd. developing CFD codes written largely in Fortran 77 running on VAX and UNIX workstations.  He then worked as part of the thermal modeling group with Bell Northern Research.  His Master's thesis work was in the area of a posteriori error estimation for Navier-Stokes equations, which is an area that is still relevant to Department of Energy scientific computing.   He worked for Beam Technologies developing the PDESolve package: a combined symbolic manipulation package and finite element solver, running in parallel on some of the earliest NSF and DOE MPP parallel computers.  He came to LBNL in 1998 to work with Phil Colella and start up the Chombo Project, now in its 13th year of development. He is currently working on his PhD in the Computer Science department at UC Berkeley.

## 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.