Nonlinear features in explicit algebraic models for turbulent flows with active scalars

• A detailed discussion of explicit algebraic turbulence models in the case of active scalars is given. In particular, we discuss the appearance of nonlinearities in the models and the need for explicit solutions of the resulting nonlinear equations. Focussing on a recently published model for two-dimensional stratified flows, we present an intuitive way of approximating the solution of a sixth-order polynomial equation for the production-to-dissipation ratio (p + g)/e of turbulent kinetic energy K. This formulation is shown to be consistent for turbulent channel flow with stable and unstable stratification. The result is important for obtaining a robust model with a correct behaviour of the turbulence production in different limits of shear and buoyancy. The results have recently been published in Lazeroms et al. (2015).

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Maskinteknik -- Strömningsmekanik och akustik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Mechanical Engineering -- Fluid Mechanics and Acoustics (hsv//eng)

Nyckelord

Algebra

Channel flow

Control nonlinearities

Kinetic energy

Kinetics

Nonlinear equations

Polynomials

Thermal stratification

Turbulence models

Dissipation ratio

Explicit algebraic models

Explicit solutions

Nonlinear features

Order polynomials

Turbulence productions

Turbulent channel flows

Turbulent kinetic energy

Shear flow

Publikations- och innehållstyp

ref (ämneskategori)

kon (ämneskategori)