Page 119 - TransAT_Tutorial_Manual

TransAT Tutorial Manual 3.3. Turbulent Heat Flux Modelling

To see the surfaces of all or each of the boundaries, choose a boundary in the drop-down list at
the top of the BCs tab. One boundary condition of each type is available to be edited and used
from the start. Additional BCs can be created by clicking on . is used to assign a selected
BC to a highlighted surface.

Creating Boundary Conditions:
In this case, an inflow is located at the X min surface, an outflow at the X max surface, a wall
at the Y max surface and symmetry boundary conditions at Y min, Z min and Z max surfaces.
The wall in Y max will be cut into two adiabetic sections at the entry and exit of the pipe and a
heated section at the center using Sub-BCs. Below is a set of step-by-step instructions to create
an inflow boundary condition and define its properties.

• Beginning with the Inflow BC, click to set the properties of the boundary condition

• Fill in the inflow properties - Tab: Basic

– Inflow Data Source: From BC
– Inflow Type: Velocity based

– Inflow profile: Turbulent
– Inflow Velocity components: u: 1 v: 0.0 w: 0.0
– Inflow Static Temperature: 300.0

• Fill in the inflow properties - Tab: Turbulence (RANS)

– Turbulent Intensity: 0.1
– Turbulent Viscosity Ratio: 60
– Temperature Variance Intensity: 0.001

– Thermal Timescale Ratio: 0.5
– Turbulent Heat Fluxe (X-, Y-, Z-directions): 1e-6

• Click to save the settings and close the window.

The inflow boundary condition has now been created.

• Proceed similarly as above to set the remaining boundary conditions with the following
properties, you will need to create a new wall BC, using the Add new boundary condi-
tion button.

c
Ascomp AG Switzerland 109 Version 5.7