Setting the Initial Conditions and Boundary Values
You define a mass flow inlet with 0.075 kg/s air inflow and a pressure outlet with relative pressure 0.0 Pa. You initialize the flow with velocity and turbulence parameters close to the flow field in the steady state.
To initialize the flow:
- To initialize the inlet velocity, select the Value to [0,0,20] m/s, which corresponds approximately to the inlet speed given the defined mass flow. node and set
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To initialize the turbulence values, you calculate the turbulence intensity and
turbulence length scale for the duct flow as functions of pipe radius and mass flow.
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To set the mass flow inlet boundary:
- Select the Value to $MassFlow. node and set
- Select the Method to Intensity + Length Scale node and set
- Select the Value to $TI. node and set
- Select the Turbulence Length Scale node and set Value to $TL.
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To set the pressure outlet boundary:
- Accept the default pressure value of 0.0 Pa.
- Select the Method to Intensity + Length Scale node and set
- Select the Value to $TI. node and set
- Select the Turbulence Length Scale node and set Value to $TL.