TURBULENCE MODELS IN CALCULATIONS OF AERODYNAMIC CHARACTERISTICS OF GAS FLOWS

Abstract

The review of the most common turbulence models in engineering calculations, which allow approximate description of turbulent flows using the Reynolds equations of motion, is carried out, and their areas of application are shown. To calculate turbulent flows by solving the Reynolds equations, a closure hypothesis is adopted for apparent turbulent stresses and other variables included in the equations.

It is noted that Businex is considered one of the main ones, which is confirmed by experimental studies of turbulence, which show that the turbulent flow is characterized by the presence of an energy cascade from large to smaller scales.

In addition, the authors considered: the semi-empirical Prandtl theory based on the assumption that turbulent motion consists of an infinite number of vortices of various scales that interact with each other and transfer energy from large scales to smaller ones, models specially adapted to a specific type of problem, for example, LES for modeling the interaction of turbulent flows, a generalized theory of developed turbulence (GDT, Generalized Theory of Turbulence), which is a theory, developed for the description and simulation of turbulent flows in various technical devices.

It is proved that one of the most common approaches is to use models with different levels of detail, starting with simpler models and moving on to more complex ones, if necessary to achieve the required accuracy. This approach is called the "ladder of models" or RANS/LES method. In particular, one of the most common turbulence models, the k-epsilon model for modeling flow in ventilation systems, can be used in the "model ladder" method to account for turbulent flows inside ventilation ducts.