Setting coupled solver parameters

The Coupled Solver parameters control the iterative coupled solution process. Generally you will not need to modify these options.

Communication Frequency

Adjust the communication frequency to define how often the thermal and flow solvers communicate for steady-state solutions. The value is the number of flow iterations which must take place before the thermal solution is performed. For example, a communication frequency of 5 means that a thermal solution will be performed every 5 iterations of the flow solver. This parameter can have a maximum value of 20.

The first communication between the two solvers starts on the following iteration:

• First iteration for models with buoyancy and the TBC_FIRST_UPDATE advanced parameter not set.

• Iteration equal to (communication frequency/2) for models without buoyancy and the TBC_FIRST_UPDATE advanced parameter not set.

• Iteration value set by the TBC_FIRST_UPDATE advanced parameter.

Maximum Temperature Change

This setting specifies a maximum temperature change for any convecting element. It defines coupled solution convergence at the coupled iteration when the temperature change on all convecting elements falls below this value.

Global Heat Imbalance Fraction

This setting specifies a normalized heat residual. The fractional change in convective heat exchange between successive coupled iterations must fall below this value for the coupled solution convergence. A value of 0.001 represents a fractional change of 0.1%.

Note:

These convergence criteria are not a true indication of model convergence. You should always check the overall heat balance for the solution listed in the message window. If the heat balance is not satisfactory (less than 1% of total heat input) then a smaller convergence criteria may be required.

How do I

How to choose values for Maximum Normalized Velocity Change and Maximum Normalized Pressure Change

Learn more

Adjusting solver parameters

Setting thermal solver parameters

Setting flow solver parameters

Understanding radiation parameters

Setting relaxation factors for the flow solver

Defining a time step for a flow analysis

Understanding the freeze flow field options

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