/GAUGE/SPH

Block Format Keyword Defines SPH gauges.

Format

Field	Contents	SI Unit Example
`gauge_ID`	Gauge identifier (Integer, maximum 10 digits)
`unit_ID`	Unit Identifier (Integer, maximum 10 digits)
`gauge_title`	Gauge title (Character, maximum 100 characters)
`node_ID`	Node identifier (Integer)
`F`_cut	Cutoff frequency (Real)	$[Hz]$
`shell_ID`	Shell identifier. Only 4-node shells can be used. (Integer)
`DIST`	Distance between gauge and shell surface > 0 Gauge in the side pointed by normal of shell surface. < 0 Gauge in the opposite side of the normal of shell surface. Default = 0 (Real)	$[m]$

SPH pressure gauges can be defined by:
- A node using a node identifier (node_ID > 0), or
- A shell element (shell_ID) and a distance (DIST). In this case node_ID must be equal to 0.
The SPH approximation is used for measuring the pressure (density) at the gauge location:(1)
$π (x) = \sum_{i, p a r t i c l e s} P_{i} V_{i} W (x - x_{i}, h_{i})$
with $x_{i}$ , $h_{i}$ , $V$ , and $P_{i}$ , respectively being the location, diameter, volume, and the pressure of particle $i$ .
A correction at order 0 applies in the above equation, whatever the correction order which are specified into the SPH properties.
The pressure may be filtered (a 4-pole Butterworth filter is used).
SPH pressure gauges and ALE or FVM gauges (/GAUGE) cannot share the same gauge_ID.