Tdyn reference manual


Turbulence modelling

Most flows of practical engineering interest are turbulent, and turbulent mixing then usually dominates the behaviour of the flow. Turbulence plays a crucial part in the determination of many relevant engineering parameters, such as frictional drag, heat transfer, flow separation, transition from laminar to turbulent flow, thickness of boundary layers, extent of secondary flows, and spreading of jets and wakes.

The turbulent states that can be encountered across the whole range of industrially relevant flows are rich, complex and varied. After one century of intensive theoretical and experimental research, it is accepted that there is no single turbulence model, that can span these states and that there is no generally valid universal model of turbulence.

Tdyn incorporates a variety of different models and options available for simulating turbulent flows. The choice of which turbulence model to use and the interpretation of its performance (i.e. establishing bounds on key predicted parameters) is a far-from-trivial matter. Next points should be considered to select one model.

In order to help in the selection of the turbulence model to be used in every case, the general features and broad limitations of different classes of model will be discussed next and guidance will be given on the practical deployment of the turbulence model most commonly used in industrial practice, the standard k-ε model.

Further information about turbulence modelling can be found in [[12]].

Remarks:

Turbulence modelling options are only available in RANSOL module.