BEGIN:VCALENDAR
VERSION:2.0
CALSCALE:GREGORIAN
PRODID:iCalendar-Ruby
BEGIN:VEVENT
CATEGORIES:Defenses
DESCRIPTION:Dissertation Defense: Accuracy and Simplicity in One Equation T
urbulence Models \n\nThe complex structure and dynamics of turbulence combi
ned with computational limitations create a fundamental barrier. Turbulence
is both rich in scale and chaotic in time\, thus time accurate predictions
of turbulent flows are out of reach for many important applications. If di
rect numerical simulations are not feasible\, we turn to turbulence modelin
g. Unfortunately\, many inexpensive popular models lack a strong theoretica
l backbone. We seek models that efficiently and accurately capture importan
t flow characteristics. Eddy viscosity models\, which model the effect of u
nresolved scales with enhanced dissipation\, are the most commonly used tod
ay.\n\nThe scaling of the time averaged energy dissipation rate as U^3/L is
fundamental\, and has been proved mathematically and supported experimenta
lly. Nonetheless\, this law is violated in numerical tests of popular model
s. Numerical dissipation introduced by commonly used multistep methods is a
potential cause or contributing factor. We explore the effects of numerica
l dissipation in multistep methods applied to the Navier-Stokes equations o
n this scaling. Additionally\, any eddy viscosity models themselves may ove
rdissipate\, particularly in the presence of boundary layers. We look to cr
eate models that fit the true behavior of the underlying equations. By enfo
rcing correct near wall behavior of the turbulent viscosity through a new t
urbulence length scale\, we prevent overdissipation in the long time averag
e while minimizing computational complexity. Motivated by enforcing model a
ccuracy in the near wall area\, the inclusion or exclusion of viscous diffu
sion in the k-equation is debated. By examining the derivation of the k-equ
ation\, we show that inclusion leads to incorrect near wall asymptotics.\n\
nAdvisor: Dr. William J Layton
DTEND:20220722T160000Z
DTSTAMP:20221205T213149Z
DTSTART:20220722T130000Z
GEO:40.444454;-79.956506
LOCATION:Thackeray Hall\, 427
SEQUENCE:0
SUMMARY:Dissertation Defense: Kiera Kean
UID:tag:localist.com\,2008:EventInstance_40483594642294
URL:https://calendar.pitt.edu/event/dissertation_defense_kiera_kean
END:VEVENT
END:VCALENDAR