Multiphase Flow for a Fuel Tank: Exercise 4—Defining Physics Modules
1. In the Flow Analysis Tree, right-click Physics and select Select Physical Models. or click 
Physics Module. The Physical Model Selection dialog box opens.
Physics Module. The Physical Model Selection dialog box opens.2. Under Available Modules, select Multiphase and click 
3. Click Close to close the Physical Model Selection dialog box.
4. In the Flow Analysis Tree select Common.
5. In the Model tab set Time Definition to Transient.
6. In the Flow Analysis Tree, select Flow.
7. In the Model tab select the following values for the options listed:
◦ Converge Criterion—0.1
◦ Under Numerics, for Relaxation set the following values:
▪ Velocity—0.5
▪ Pressure—0.5
◦ Under Numerics, for Diagonal Relaxation set the following values:
▪ Velocity—0.5
▪ Pressure—2
◦ Under Numerics, for Numeric Scheme set the following values:
▪ Velocity—2nd Order Upwind
▪ Density—Upwind
◦ Gravity Force—Yes
▪ g—0, 0, -9.81 m/s2
◦ Gauge Pressure—No
8. Under Physics, select and right-click Multiphase.
9. Select Add Component. Do this twice.
10. Two values comp_1 and comp_2 are added in the Properties panel for Components.
11. Rename comp_1 as fuel and rename comp_2 as air.
12. In the Model tab, for Numerics, set Implicit Method to No.