Natural Convection: Exercise 5—Assigning Boundary Conditions

Specifying Top and Bottom Boundary Conditions

1. Under Boundary Conditions, for General Boundaries select top_surface and bottom_surface.

2. In the Model tab select the following values for the options listed:

◦ Flow—Symmetry

Specifying Inner Surface Boundary Conditions

1. Under Boundary Conditions for General Boundaries select inner_surface.

2. In the Model tab select the following values for the options listed:

◦ Heat—Specified Temperature

◦ Temperature—373 K

Specifying Outer Surface Boundary Conditions

1. Under Boundary Conditions for General Boundaries select outer_surface.

2. In the Model tab select the following values for the options listed:

◦ Heat—Specified Temperature

◦ Temperature—327 K

Specifying Volume Conditions

1. To set the fluid, click

Materials. The Material Selection dialog box opens. The fluid properties are set automatically when you select a new fluid.

2. For fluid domain CONCENTRIC_ANNULUS select air. Change the default value of Density from Constant Density to Ideal Gas Law.

3. Click OK.

4. In the Properties panel, Model tab, set the following:

◦ For Flow, set Viscosity to 3.548e-05 Pa-s

◦ For Heat, set

▪ Conductivity to Constant Conductivity

▪ Initial Conditions to 350 K