[GTP] MMM/GTP seminar at NCAR November 8, 2010

[Carolyn Mueller]

New Developments in Turbulence Modeling. II. Applications

 

Harish Gopalan and Stefan Heinz

Wind Energy Research Center/ Department of Mathematics

University of Wyoming

 

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.

November 8, 2010
FL2 Main Auditorium
Room 1022
Lecture 11:00 am

-- 
Carolyn Mueller
NCAR IMAGe
1850 Table Mesa Drive 
Boulder, CO 80305 
www.image.ucar.edu 
Tel: 303 497-2491
Fax: 303-497-2483