Fluid Analysis Tab

Setting Item

Notes

Analysis Type

Steady-State Analysis

There is no time dependency.

Transient Analysis

Transient states are analyzed.

Options

Notes

Laminar Flow/Turbulent Flow

Executes calculation assuming the flows are either laminar or turbulent.

To calculate turbulent flow, select the turbulent flow model in the [Detailed Settings of Fluid Analysis] dialog box.

Flow Type

Internal flow or external flow can be selected.

This option affects two settings.

・ Outer boundary conditions are automatically determined.

(The automatic determination can be deselected on the [Fluid tab (Fluid-Thermal tab)] of the outer boundary condition. Refer to [Outer Boundary Condition] for how to set outer boundary.)

Refer to [Boundary Condition of Fluid Analysis] of the Technical Notes for the details of outer boundary types.

・The fluid domain depends on whether internal flow or external flow is selected for the behavior of the automatically created fluid. (if [Automatic Fluid Creation] selected)

If [Internal Flow] is selected, a fluid domain is created inside the solid domain.

If [External Flow] is selected, a fluid domain is created outside the solid domain.

If [Automatic Fluid Creation] is selected, a model of fluid can be automatically created.

Applicable when a solid domain has been created.

The model of fluid is automatically created based on whether the internal or external flow is selected.

Click the button . The [Automatic Fluid Domain Creation] dialog will appear. Fluid type, shape, and other parameters can be set.

Initial Value/Restart

If Use the last analysis results is selected,
the previous results which were not converged or aborted can be used as initial values.

If Use another analysis results (Results Import) is selected, an analysis model that was already analyzed or the results file is used as the initial values for the calculation.

The analysis model or the results file is specified on the [Results Import] tab.

Click the [Detailed Setting for Restart] button to show a dialog box.

If Calculate quasi-steady state is selected, the analysis with finite timesteps is applied when restarting.
Effective for the case where steady state does not exist or calculation does not converge due to the non-steady vibration.
An instantaneous state of the vibration is output.

If Hand over the time is selected, the time of the previous analysis results or another analysis results is handed over.

If the results of the previous analysis were up to 10 s for example, this option allows the analysis to continue without removing the results up to 10 s of the previous analysis.
(It corresponds to selecting [Continue from the last session] on the [Transient Analysis] tab)
If [Hand over the time] is not selected for the transient analysis, the results up to 10 s are removed and the analysis starts using the results at 10 s as an initial value.

If the analysis type of fluid is steady-state or if transient analysis is applied for the thermal or diffusion analysis, all the previous results are removed and the analysis starts at 0 s.

Different analysis conditions from the previous analysis can be applied as well.

The setting here automatically determines the settings of [Continue from the last session] on the [Transient Analysis] tab and [Import Type] on the [Results Import] tab.

Diffusion Analysis

For diffusion analysis, select [Diffusion Analysis] in the [Option].

See Diffusion Analysis of technical note for more information.

Click to show the [Diffusion Analysis Setting] dialog box.

Free Surface Analysis (VOF Method)

For free surface analysis (VOF method), select [Free Surface Analysis (VOF method )] in the [Option].

See [Free Surface Analysis (VOF method)] for more information.

Click to show the [Multiphase Flow Setting]] dialog box.

Layer Mesh Setting

Enables the general settings for the layer mesh of the wall surface.
If the individual setting is not applied to each boundary condition, the settings here are applied.

Click this button . The [Layer Mesh Setting] dialog box will appear.

Ambient Value Setting

The option [Analyze using the material properties depending on ambient values] can be selected.

Specify ambient values (ambient temperature and ambient pressure).

Click this button . The [Ambient Value Setting] dialog box will appear.

Detailed Setting

Sets the parameters relating to the accuracy and convergence.

Click this button . The [Detailed Setting of Fluid Analysis] dialog box will show up.

Notes

Be sure that if you want to take into account the buoyancy ,

select [Thermal Analysis] on the [Solver] tab, and select [Take into account buoyancy] on the [Fluid-Thermal Analysis] tab.