The particle-tracking procedure is attached to the GENTRA option of PHOENICS. It computes the volume fractions of the fluids in each cell, based on particle locations, and then calculates the densities which are to be employed in the momentum equations.
Limitations: 2-D X-Y plane; single-track line (no break up)
How to use:
The Q1 file Apart from the conventional settings required for the problem in question, the following settings are specific to the particle-tracking procedure:
STORE(C1) and RHO1=GRND -- for density calculationThere are two parts in the Q1 file; the first part from Group 1 to Group 23 is for standard Q1 settings and the second part after Group 23 is for GENTRA settings.
LG(30)=T -- to activate particle tracking procedure
RG(30) -- to define the face from which the first particle will enter the calculation domain. RG(30)=1 - from West; north RG(30)=2 - from East; |------| RG(30)=3 - from South; west| | east RG(30)=4 - from North; |------| south
RG(1) -- density of the fluid on the left side of the track
RHO2 -- density of the fluid on the right side of the track
|--> left side |/ / ---> | right / --> | / / / / / --> |-----------------
The most convenient way for users to set a problem is to load GENTRA library case 722 and then modify the first part according to the problem description and then modify only Group 2 of the GENTRA settings, that is Boundary conditions for particles.
Users should specify the initial particle positions there. The program will
automatically perform a linear interpolation between particles in order to adjust the
distance between two adjacent particles.
Therefore only two particles need to be specified for a straight line of the initial distribution as described in case 722. For other shapes of the initial distribution, users have to specify a sufficient number of particles to produce the desired result.
Sub-routine trkden.htm in phoenics/d_earth/d_opt/d_gentra
This is the routine for the density calculation. Users must re-dimension local variable array to be consistant with NX,NY specified in Q1.
gentra.htm in phoenics/d_earth/d_opt/d_gentra
group 9 -- To calculate density (no users' action is needed)
group 11 -- Users must set initial density distribution; note that RG(6) is used only for library case g722
group 19 -- To call tracking routine (no user action is needed)
How to view tracks:
followed by t <return> and then by T1-T2 <return>
where T1 and T2 are integer numbers defining
the first time step and the last time step;