Boundary Conditions / Forces
First the inlet must be defined using the Fluid Flow Conditions. In the Add drop down menu by Fluid Flow Conditions, select Inlet then using the face selection tool define an inlet at the low end of the duct. Make sure to input the velocity magnitude as 10 [m s^-1].
Once the inlet is defined, the outlet is next. In the same menu, use the outlet tool to define an outlet at the small end of the duct. Assign a Gauge Static Pressure of 0 psi.
Next a wall condition must be added to all surfaces that are not already defined. Wall can be found in the same Add menu as the previous conditions. AIM will automatically create the walls once the option is selected, AIM selects every face that doesn't already have a constraint on it.