# /GAUGE/SPH

Block Format Keyword Defines SPH gauges.

## Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
/GAUGE/SPH/gauge_ID/unit_ID
gauge_title
node_ID     Fcut shell_ID DIST

## Definitions

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)

Fcut Cutoff frequency

(Real)

$\text{[Hz]}$
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)

$\left[\text{m}\right]$

1. 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.
2. The SPH approximation is used for measuring the pressure (density) at the gauge location:(1)
$\pi \left(x\right)={\sum }_{i,particles}{P}_{i}{V}_{i}W\left(x-{x}_{i},{h}_{i}\right)$
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.

3. The pressure may be filtered (a 4-pole Butterworth filter is used).
4. SPH pressure gauges and ALE or FVM gauges (/GAUGE) cannot share the same gauge_ID.