Apply source terms at start of time step

[mcgratta]

This case produces a fictitiously high HRR in the last time step because of a 1 step lag on the addition of gases from particles. The larger problem has to do with source terms typically being evaluated in the second half of the time setp.

&HEAD CHID='geom' TITLE='Test intersection of GEOM XB and INIT XB with particles' /

&MESH IJK=20,20,20, XB=-1,1,-1,1,-1,1 /

&TIME T_END=10 /

&VENT DB='XMIN', SURF_ID='OPEN'/
&VENT DB='XMAX', SURF_ID='OPEN'/
&VENT DB='YMIN', SURF_ID='OPEN'/
&VENT DB='YMAX', SURF_ID='OPEN'/
&VENT DB='ZMIN', SURF_ID='OPEN'/
&VENT DB='ZMAX', SURF_ID='OPEN'/

&REAC FUEL='METHANE'/
&COMB INITIAL_UNMIXED_FRACTION=0/

GEOM XB=-.5,0,-.5,0,-.5,0 /

!radius gives 1 m2 area with 10,000 particles (1 m^2 = 10,000 * 4*pi*r^2)

&SURF ID='heat flux', HRRPUA=100, COLOR='RED', RADIUS=0.002820947917739, GEOMETRY='SPHERICAL'/

&PART ID='burning particles', SAMPLING_FACTOR=10, SURF_ID='heat flux', STATIC=T,
      QUANTITIES='PARTICLE TEMPERATURE','PARTICLE DIAMETER'/

&INIT XB=-.5,.5,-.5,.5,-.5,.5, PART_ID='burning particles', N_PARTICLES=10000/

&SLCF DB='YMID', QUANTITY='HRRPUV', CELL_CENTERED=T /

&TAIL /