# 4.10. Point Sources¶

Point sources (PS) are used in place of mass inlets where either the geometry and/or grid resolution prohibit proper boundary condition specification. For example, a point source may be used to model an injector with dimensions smaller than the grid. Point sources may be defined within a single computational cell, along a plane, or as a volume of computational cells.

Point sources introduce mass directly into a computational cell unlike a boundary condition which specifies flow along a cell face. One consequence of this implementation is that point sources are subjected to convection/diffusion forces and may not travel parallel to the specified directional preference. Directional preference may be specified with a velocity vector (i.e., PS_U_g, PS_V_g, etc.), however, directional preference is not required.

Examples showing how to setup point sources can be found in: legacy_tutorials/point_source_spiral

## 4.10.1. Creating a Point Source Region¶

To define a point source, there must be a region already defined in the Regions Pane.

To create a new point source, press the button which will bring up the Region Selection dialog. Select a region to associate with the new point source and press OK.

Mass flow rate The mass flow rate is the rate of mass introduced for the point source. It has a default value of 0.0 kg/s

Temperature The temperature only applies to cases when energy equations are turned on under Model Setup. It has a default value of 293.15 K.

Velocity The velocity of the mass introduced by the point source is always available. The default velocity is zero.