.. include:: /icons.rst

.. _point_sources:

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``

Creating a Point Source Region
------------------------------

To define a point source, there must be a region already defined in the
:ref:`Regions Pane <regions>`.

Add/Delete Point Sources
------------------------

To create a new point source, press the |add| 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 :ref:`Model Setup <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.