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Setup → Boundary Conditions → outlet

a.Select vapor from the Phase drop-down list.

b.Click Edit... to open the Pressure Outlet dialog box.

i.In the Multiphase tab, retain the default value of 0 for Backflow Volume Fraction.

ii.Click OK to close the Pressure Outlet dialog box.

18.4.8. Operating Conditions

1. Set the operating pressure.

Setup → Boundary Conditions → Operating Conditions...

a.Enter 0 Pa for Operating Pressure.

b.Click OK to close the Operating Conditions dialog box.

18.4.9. Solution

1.Set the solution parameters.

Solution → Solution → Methods...

a.Select Coupled from the Scheme drop-down list in the Pressure-Velocity Coupling group box.

b.Retain the selection of PRESTO! from the Pressure drop-down list in the Spatial Discretization group box.

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c.Select QUICK for Momentum and Volume Fraction.

d.Retain First Order Upwind for Turbulent Kinetic Energy and Turbulent Dissipation Rate.

e.Enable Pseudo Transient.

f.Enable High Order Term Relaxation.

The relaxation of high order terms will help to improve the solution behavior of flow simulations when higher order spatial discretizations are used (higher than first).

2.Set the solution controls.

Solution → Controls → Controls...

a.Set the pseudo transient explicit relaxation factor for Volume Fraction to 0.3.

3.Enable the plotting of residuals during the calculation.

Solution → Reports → Residuals...

a.Ensure that Plot is enabled in the Options group box.

b.Enter 1e-05 for the Absolute Criteria of continuity, x-velocity, y-velocity, k, and epsilon.

Decreasing the criteria for these residuals will improve the accuracy of the solution.

c.Click OK to close the Residual Monitors dialog box.

4.Initialize the solution.

Solution → Initialization

a.Retain the default selection of Hybrid from the Initialization group box.

b.Click More Settings... to open the Hybrid Initialization dialog box.

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c.Enable Use Specified Initial Pressure on Inlets in the Initialization Options group box. The velocity will now be initialized to the Initial Gauge Pressure value that you set in the Pressure Inlet boundary condition dialog box. For more information on initialization options, see hybrid initialization in the Fluent User's Guide.

d.Click OK to close the Hybrid Initialization dialog box.

e.Click Initialize to initialize the solution.

Note

For flows in complex topologies, hybrid initialization will provide better initial velocity and pressure fields than standard initialization. This will help to improve the convergence behavior of the solver.

5.Save the case file (cav.cas.gz).

File → Write → Case...

6.Start the calculation by requesting 400 iterations.

Solution → Run Calculation → Advanced...