Probes

Probe particles are created in order to extract accurate post-processing information from a particular location, such as a FLUID or a WALL or a MOVINGWALL phase.

Commands

Note: It is possible to define both static and moving probe particles.

probes
{
    probe
    {
        probe_type            volumeprobe                 
        probe_name            volumeprobeExample          
        probe_cntr            "0.0 0.0 0.0”               
        probe_rad             0.25                        
        probe_radodx          5                           
        probe_phase           3                           
        probe_shiftingaware   true
    }
    probe
    {
        probe_type            surfaceprobe                
        probe_name            surfaceprobeExample         
        probe_cntr            "0.0 0.0 0.0"               
        probe_rad             0.5                         
        probe_radodx          9.5                         
        probe_thck            0.05                        
        probe_thckodx         3                           
        probe_nrmvec          "10.0 0.0 0.0"              
        probe_phase           3    
        probe_shiftingaware   true                           
    }
    probe
    {
        probe_type            solidprobe                  
        probe_name            solidprobeExample           
        probe_cntr            "1.0 20.0 3.0"              
        probe_rad             1.0                         
        probe_radodx          15.5                        
        probe_phase           2 				
        probe_movewith        true                               
    }
    probe
    {
        probe_type            flowrateprobe		  
        probe_name            flowrateprobeExample        
        probe_cntr            "1.0 -1.0 -100.0"	    
        probe_thck            0.2   			  
        probe_thckodx         2.5 			    
        probe_nrmvec          "0.0 1.0 0.0"               
        probe_tanvec          "5.0 0.0 0.0"               
        probe_points_file     filename                    
        probe_phase           3   
        probe_shiftingaware   true                        
    }
}

Definitions


Command	Contents	SI Unit Example
`probe_type`	Type of the probe used Options `volumeprobe` assesses fluid properties `surfaceprobe` assesses fluid properties (mass flow). `solidprobe` assesses solid body properties. `flowrateprobe` is essentially a MASSFLOW equivalent.
`probe_name`	Probe name
`probe_cntr`	Probe particle location Note: When `flowrateprobe` is comprised of multiple particles, `probe_cntr` represents a sort of reference point in cases where the probe is supposed to move.
`probe_rad`	Radius of the probe particle Note: Influences the sample size.	Unit: [m]
`probe_radodx`	Radius of the probe as a function of $d x$ Tip: For example, when `probe_radodx` is set as 3.0, this implies $3.0 * d x$ . Attention: If both `probe_rad` and `probe_radodx` are specified, the latter one takes precedence. Default = kernel cut-off size (3.0 for quintic spline)
`probe_phase`	In cases of: `volumeprobe`, `surfaceprobe` and `flowrateprobe` this command specifies which phase motion the probe should follow. Tip: For example, if you specify phase 3, and that phase is a MOVINGWALL with assigned rotation, than the probes will follow the same motion. `solidprobe`, this command specifies which solid phase is monitored.
`probe_movewith`	Command `solidprobe` points to a particular phase for monitoring, where this command determines whether the probe is also moving with that phase or not. Note: This command is applicable only to the `solidprobe`. Options true false Default = false
`probe_thck`	This command specifies the absolute thickness of the probes. Commands `flowrateprobe` and `surfaceprobe` are effectively 2.5D-like entities, where their definition is 2D, but in order to function properly, they need to consider a certain space before and after them and require a thickness parameter.	Unit: [m]
`probe_thckodx`	Same as the above command, except that it specifies the probe thickness as a relative function of the kernel size. Tip: For example, when `probe_radodx` is set as 3.0, this implies $3.0 * d x$ . Default = $1.0 * d x$
`probe_nrmvec`	Vector specifying the surface normal of the probe. Flow passing in the same direction as this vector will be noted as a positive value flow.
`probe_tanvec`	Specifies a vector which is co-planar with probe surface and at the same time defines the probe grid direction. Note: This command is optional.
`probe_points_file`	Makes it possible to have a separate file with cloud point data (simple X, Y, Z coordinates; delimiter is space) and use it as a definition for the `flowrateprobe` probe particles. Note: Only applicable to `flowrateprobe` type.
`probe_shiftingaware`	Enables the probes to consider the real convective velocity when using transport velocity or APD schemes. Tip: It is recommended that this option remains true. Default = true

PROBE Output File

Probes can provide a broad set of information about the area which they are monitoring. This data can be torque or forcing data (solid probes only), mass or volume flow rates, pressure values, density, viscosity or velocity. Various applications require different measurements not just in terms of the monitored variable, but also in terms of time sampling or distinguishing the flow direction. In order to tackle all of these options, the PROBE output file can contain numerous columns.

The following is a list of several keywords which help explain the meaning of the columns, followed by a few examples.

Note: The asterisk * symbol means that you can find other extensions before or after the keyword.

i - instantaneous information
pta - periodic time average (averaged over the time between two outputs)
TIME - time
CNTR* - probe center
CVEL* - probe center velocity
NRMVEC* - normal vector of the probe
NPART - average number of particles per 1dx thickness of probe
oap - summation over all fluid phases
abs* - absolute (does not consider probe velocity)
rel* - relative (relative to probe velocity)
*Vol* - Volume flow rate
*Mss* - Mass flow rate
*Co* - Component of flow in the probe normal direction
*Flow - flow rate

Examples of column headers:

pta_absVolFlow_1[m^3/s]: Periodic time averaged absolute volumetric flow of phase 2.
pta_relMssCoFlow_2[kg/s]: Periodic time averaged relative mass flow in the direction of the probe normal for phase 2.
pta_relVolFlow_oap[m^3/s]: Periodic time averaged relative volumetric flow overall all phases (volumetric flow of all fluid phases).
i_CNTR-Y[m]: Instantaneous location of the probe center in Y direction.
pta_absMssCoFlow_7[kg/s]: Periodic time averaged absolute mass flow in the direction of the probe normal for phase 7.
Note: To clarify, the term periodic time average implies a value that is time averaged over the period between two required outputs (dt_phaseinfo). The ns_phaseinfo command defines the number of samples that will be taken over the period of dt_phaseinfo and then averaged to provide the periodic time average value in the output.