The doctoral dissertations of the former Helsinki University of Technology (TKK) and Aalto University Schools of Technology (CHEM, ELEC, ENG, SCI) published in electronic format are available in the electronic publications archive of Aalto University - Aaltodoc.
Aalto

New Two-Equation Turbulence Model for Aerodynamics Applications

Antti Hellsten

Dissertation for the degree of Doctor of Science in Technology to be presented with due permission of the Department of Mechanical Engineering for public examination and debate in Auditorium K216 at Helsinki University of Technology (Espoo, Finland) on the 20th of February, 2004, at 12 o'clock noon.

Dissertation in PDF format (ISBN 951-22-6934-1)   [12117 KB]
Dissertation is also available in print (ISBN 951-22-6933-3)

Abstract

Two-equation turbulence modelling for computational fluid dynamics and especially for analyses of high-lift aerodynamics applications is studied in depth in this thesis. Linear Boussinesq-type modelling is abandoned and a more sophisticated explicit algebraic Reynolds stress modelling (EARSM) approach is chosen as a constitutive relation between the turbulent stress tensor and the mean-velocity gradient and turbulent scales. The proposed techniques to extend the EARSM method for significantly curved flows are critically discussed and assessed.

The main focus of this study is on development of a new scale-determining two-equation model to be used with the EARSM as a constitutive model. This new k – ω model is especially designed for the requirements typical in high-lift aerodynamics. In the model development, attention is especially paid to the model sensitivity to pressure gradients, model behaviour at the turbulent/laminar edges, and to calibration of the model coefficients for appropriate flow phenomena. The model development is based on both theoretical studies and numerical experimenting. A systematic study is carried out to find the most suitable operational second scale-variable for this model. According to this study, ω itself was chosen. The developed model is finally assessed and validated for a set of realistic flow problems including high-lift aerofoil flows.

Keywords: computational fluid dynamics, turbulence modelling, high-lift aerodynamics, k-omega model, explicit algebraic Reynolds stress model

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© 2004 Helsinki University of Technology

Last update 2011-05-26