[GTP] GTP MMM- seminar at NCAR Monday November 8-- Harish Gopalan REMINDER
Silvia Gentile
sgentile at ucar.edu
Fri Nov 5 17:43:44 MDT 2010
New Developments in Turbulence Modeling. II. Applications
Harish Gopalan and Stefan Heinz
Wind Energy Research Center/ Department of Mathematics
University of Wyoming
November 8 at 11am
FL2 main auditorium
Refreshments at 10:45am
For the foreseeable future we have to calculate turbulent flows as
observed in reality on the basis of equations that involve a turbulence
model. The development of computational methods that have a predictive
power requires the use of equations for large eddy simulation (LES). In
such equations we need a subgrid-scale (SGS) turbulence model that
accounts for the interaction of large and small scales. Existing SGS
models face three kinds of problems. First, the consistency of models is
not always clear: a turbulence model describes correlations of a
stochastic process, but there are SGS models for which an underlying
stochastic process does not exist. Second, most SGS models need
adjustments to the flow considered: such methods have a limited
predictive power. Third, LES are often too expensive for applications to
wall-bounded flows at high Reynolds numbers, which have to be computed
in many applications. Theoretical solutions to these problems were
described in the first part of the two talks. The application of these
solutions to simulations of several turbulent flows will be presented in
this talk. First, the validation of the dynamic turbulence model is
presented with regard to channel flow simulations. It is shown that the
new dynamic model overcomes the stability problems of existing dynamic
models. Initial results of applications of the dynamic turbulence model
to simulations of the neutral atmospheric boundary layer are shown. The
unified turbulence model is also validated in terms of channel flow
simulations. Then, the application of the unified turbulence model to
studies of turbulent swirling jets is discussed. The results obtained
for flows involving vortex breakdown reveal significant improvements
compared to previously applied hybrid methods.
Silvia Gentile
NCAR IMAGe
1850 Table Mesa Drive
Boulder, CO 803035
www.image.ucar.edu
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