Boundary condition setting

Update: June 20, 2021

In XSim, you can set the boundary condition to the analyzed shape's region in the "Flow Boundary Condition" page. Select the region in navigation view on left side of the window and click Set button to set the boundary condition.

The boundary conditions that can be set are as follows.

Table 1. The boundary conditions that can be set
Boundary condition	Description
Fixed flow velocity	Sets the flow velocity at the region as a 3-dimensional vector. The unit is m/s.
Fixed mass flow rate	Sets the flow rate through the region in mass. The unit is kg/s.
Fixed volume flow rate	Sets the flow rate through the region in volume. The unit is m³/s.
Fixed normal direction velocity	Sets the flow velocity at the region as a scalar value. The direction of the flow is normal to the region. The unit is m/s.
Fixed static pressure	Sets the static pressure at the region. The unit is Pa.
Fixed total pressure	Sets the total pressure (=static pressure + dynamic pressure) at the region. The unit is Pa.
Natural inflow/outflow	Set the region as a surface with inflow/outflow can be occur. Either inflow or outflow is determined by the calculated flow near the surface.
Slip wall	Sets the region as a frictionless wall.
Stationary wall	Sets the region as a wall with zero velocity.
Moving wall	Sets the region as a wall with a constant velocity. The velocity is set by a 3-dimensional vector in m/s.
Rotating wall	Sets the region as a wall with a constant rotational speed. This is defined by the rotation axis and the rotation speed (in °/s). This condition is usually used to set a cylindrical or spherical region.
Symmetry	Sets the region as plane of symmetry and the exact same flow is occurring in reverse from the opposite side.
Boundary face mapping	Sets the pair of region and the flow velocity and pressure on one region will be mapped to the other.

For thermal analysis, the following thermal boundary conditions can be set to the walls (slip wall, stationary wall, moving wall, and rotating wall).

Table 2. The thermal boundary conditions that can be set
Boundary condition	Description
Adiabatic	Sets the wall to be insulated with no heat transfer.
Fixed temperature	Sets the wall to keep a constant temperature. The unit is K (Kelvin).
Fixed heat flux	Sets the heat flux (the amount of heat that crosses a unit area in a unit time) and the initial temperature. The units are W/m2 and K.
Fixed heat source	Sets the heat generation rate and initial temperature. The units are W and K.
Fixed heat transfer coefficient	Sets the heat transfer coefficient (that depends on the flow and wall surface conditions), the initial temperature, and the temperature outside the analysis area. The units are W/(m²・K), K, and K, respectively.