Gelonia Dent

New Orleans 2001

Born:

place: born in New Orleans, Louisiana and raised in Atlanta, Georgia

B.S. 1988 Department of Mathematics,University of Georgia, Athens, GA; Sc.M. 1991 Department of Mathematics, Clark Atlanta University, Atlanta, GA; Sc.M. 1997 Department of Engineering, Brown University

Ph.D. Applied Mathematics
(1999), Brown University

thesis: *Aspects of Particle Sedimentation in Dilute Flows at
Finite Reynolds Numbers*; Advisor: Martin Maxy

research staff member in the Numerical Analysis Group at the IBM T.J. Watson Research Center in Yorktown Heights, NY

Dr. Dent was born New Orleans, Louisiana and raised in Atlanta, Georgia. She received her B.S. in mathematics from the University of Georgia at Athens. She then received a Masters degree in mathematics from Clark Atlanta University and finally a Ph.D. in applied mathematics from Brown University's Division of Applied Mathematics in May 1999. Her area of research is fluid dynamics. Her work focuses on the simulation of dispersed two phase flows and she is interested in applications to bio-fluids and mathematical finance. She is a research staff member in the Numerical Analysis Group at the IBM T.J. Watson Research Center in Yorktown Heights, NY.

ARESEARCH INTEREST

Area of research is fluid dynamics. Her work focuses on the simulation of dispersed two phase flows and she is interested in applications to bio-fluids and mathematical finance.

bstract of Ph.D. thesis: The purpose of these studies is to
examine dilute two-phase flows at finite Reynolds numbers along
two main themes. First, to investigate the sedimentation of solid
particles arranged in a regular periodic lattice and to determine
both sedimentation rates and flow characteristics over a range
of finite Reynolds numbers and particle concentrations up to 20%.
This is a canonical problem in sedimentation theory and should
provide useful insights into the dynamics of two-phase flow. Second,
to investigate a simplified, approximate method for calculating
dispersed two-phase flow using a force-coupling model that employs
the fluid force on the individual particles to represent the particulate
phase as a distributed body force action on the fluid phase. This
makes the equations of motion for finite Reynolds number flows
suitable to be solved numerically, and to be independent of the
choice of algorithms. A spectral/*hp* element direct numerical
method is also used to solve the time dependent Navier-Stokes
equations for flow through periodic arrays of cylindrical and
spherical particles. The DNS calculations more accurately model
the flow dynamics and is used to validate the results of the force-coupling
model.

The two dimensional problem was used as a test of the DNS and
the results agree well with those of other numerical simulations.
Analyzing the three dimensional problem proved to be informative.
Determining the relationships between the superficial velocity
or sedimentation velocity, the external force on the particles
and flow structure as the volume fraction and Reynolds number
are varied were the main goals. For Stokes flow conditions the
sedimentation velocity decreases as the volume fraction is increased.
At finite Reynolds numbers, this is countered by an interaction
between the particles and the wakes when the system is dilute.
As the volume fraction increases, the velocity is hindered by
the particles and the settling rate decreases so that the flow
experiences a *blocking effect*. Flow separation is delayed
till higher Reynolds numbers. Comparing the force-coupling model
for spherical particle motion in dilute flows to the DNS show
that it successfully captures the flow dynamics and reproduces
observed flow characteristics from experimental data as well.
As a first approximation method it proves to be efficient and
consistent.

PUBLICATION

3. **G.L. Dent**, and M.R. Maxey, __Particle Sedimentation
in Dilute Flows at Finite Reynolds Numbers__. Bulletin of American
Physical Society, **44**, No.8, p. 48, 1999.

2. **G.L. Dent**, and M.R. Maxey, __Flow past a periodic
array of particles at finite Reynolds numbers__. Bulletin of
American Physical Society, **43**, No.9, p. 2027, 1998

1. M.R. Maxey and **G.L. Dent **__Force-coupled simulations
of particulate flows: random suspensions__.

Bulletin of American Physical Society, **43**, No.9, p. 2048,
1998

.

at Cornell 2000

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