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Problem Specification |
Step 5: Solve!
We'll use a second-order discretization scheme.
Main Menu > Solve > Controls > Solution...
Change Density, Momentum, Turbulence Kinetic Energy, Turbulence Dissipation Rate, and Energy all to Second Order Upwind. Leave Pressure and Pressure-Velocity Coupling set to the default methods (Standard and SIMPLE, respectively). The other Pressure and Pressure-Velocity Coupling methods are useful for flows with particular characteristics not present in our problem.
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https://confluence.cornell.edu/download/attachments/90745530/05_solution_controls.jpg?version=2 |
Click OK.
Set Initial Guess
Initialize the flow field to the values at the inflow:
Main Menu > Solve > Initialize > Initialize...
In the Solution Initialization window that comes up, choose inflow under Compute From. The X Velocity for all cells will automatically be set to 1 m/s, the Y Velocity to 0 m/s and the Gauge Pressure to 0 Pa. These values have been taken from the inflow boundary condition.
Click Init. This completes the initialization. Then click Close.
Set Convergence Criteria
FLUENT reports a residual for each governing equation being solved. The residual is a measure of how well the current solution satisfies the discrete form of each governing equation. We will iterate until the residual for each equation falls below 1e-6.
Main Menu > Solve > Monitors > Residual...
Change the residual under Convergence Criterion for continuity, x-velocity, and y-velocity, energy, k, and epsilon all to 1e-6.
Also, under Options, select Print and Plot. This will print the residuals in the main window and plot the residuals in the graphics window as they are calculated.
Click OK.
This completes the problem specification. Save your work:
Main Menu > File > Write > Case...
Type in plate.cas for Case File. Click OK. Check that the file has been created in your working directory. If you exit FLUENT now, you can retrieve all your work at any time by reading in this case file.
Iterate Until Convergence
Start the calculation by running 10,000 iterations. The solution will converge before 10,000 iterations are performed, which will stop the iteration process.
Main Menu > Solve > Iterate...
In the Iterate Window, change the Number of Iterations to 10000. Click Iterate.
The residuals for each iteration are printed out as well as plotted in the graphics window as they are calculated.
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https://confluence.cornell.edu/download/attachments/90745530/05_residuals.jpg?version=2 |
The residuals fall below the specified convergence criterion of 1e-6 in approximately 1623 iterations.
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https://confluence.cornell.edu/download/attachments/90745530/05_iterations.jpg?version=2 |
Save the solution to a data file:
Main Menu > File > Write > Data...
Enter plate.dat for Data File and click OK. Check that the file has been created in your working directory. You can retrieve the current solution from this data file at any time.
Go to Step 6: Analyze Results