<1>The following codes are copied from Ground.for: ~~~~~~~~~~~~~~~~~~~~~``` IF(IGR.EQ.13) GO TO 13 IF(IGR.EQ.19) GO TO 19 ~~~~~~~~~~~~~~~~~~~~~~ What should be done to make the first condition (IGR.EQ.13),i.e. the Group 13 is accessed, satified? I set USEGRD=T in Q1 file.

<2>The modification in Q1 file will be resumed after the earth is runed. Why?

1) If usegrd=t, then group 19 will always be accessible, but group 13 will only be accessed if CO=GRND or VAL=GRND for the dependent variable in question, ie in the Q1 file (or via the VR Editor GUI) define a patch (via user-defined object in the VR Editor) to specify the spatial and temporal location of the source or boundary-condition region. Then define the COVAL for the required variable, eg. COVAL(patch_name,V1,GRND,GRND) means that for the patch named "patch_name", group 13 of GROUND will be visited for V1 so that the PHOENICS CFD solver can access the user-set values of CO and VAL in the source term S=T*CO*(VAL-V1) where T is the patch type (namely volume, cell, east area or whatever). Thus, in Group 13 of GROUND you will to introduce the appropriate logic in the Co and VAL sections of GROUND, such as for example in the CO section to define CO=1.5*abs(V1), the user codes:

IF(NPATCH.EQ.'patch_name) THEN

IF(INDVAR.EQ.V1) THEN

L0CO=L0F(CO)

L0V1=L0F(V1)

DO J=1,NXNY

F(L0CO+J)=1.5*ABS(F(L0V1+J)

ENDDO

ENDIF

ENDIF

2) Don't understand the question.