Boundary conditions define how a system (for example, a structure or a fluid) interacts with the environment. 

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A boundary condition consists of three parts(you can click the type name for further instructions):

1. Boundary condition types: 

   • Velocity inlet and Velocity outlet

   • Pressure inlet and Pressure outlet

   • Wall

   • Periodic

   • Symmetry

   • Wedge

   • Custom

   • Empty 2D

2. Boundary condition assignments: A boundary condition is only usually assigned to the boundary of domain. Each boundary condition must be connected to at least one surface, where something enters or exits the domain.

3. Boundary condition values: For most cases, a single value of a given variable(velocity, temperature, pressure…) will be defined as boundary conditions. The user can assign the value based on the real life measurement.

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To create a new boundary condition, click on the '+' button beside Boundary conditions. Pick the desired type from the list:

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Figure 4: Boundary condition setting step 1

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After creating a boundary condition, input the boundary condition values and assign the desired entities by clicking on them on the model.

 

 

 

 

 

 

 

 

 

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Figure 5: Boundary condition setting step 2

 

There are some common conditions in real life to help the user understand the boundary condition better.

• Fan: Velocity inlet/outlet can be set on the surface of the fan.

• Open Vent/Window: There is no need for setting for the open vent/window since the air flow expands freely and is not forced. 

• Contaminant outlet: If a boundary condition simulates a contaminant with natural diffusion. We need to specify the contaminant’s concentration for our model using the Custom type. If the contaminant outlet is forced flow we need to specify the contaminant’s concentration, Velocity and even pressure for our model using Custom type.