---------- PIL logical, default F -------
When set to T in a Q1 file, Q1QUIT will suppress the interactive session regardless of
the setting of TALK.
If set to T interactively, it will act as if END had been entered. In either case, the Q1 file will also be unconditionally overwritten by the instruction stack or the COPYQ1 file, depending on the setting of DMPSTK.
If the file does not exist, it proceeds to write the files; however, if Q2 does exist, it processes any PIL, In-Form or > OBJ and, if they are legitimate, appropriately modifies what it subsequently writes to Q1ear etc.
For example, if the Q2 contains the single line:
restrt(all)inspection of the subsequently-written Q1EAR will reveal that the FIINIT values of all variables have been set equal to READFI.
Similarly, if the Q2 contains object-introducing lines such as:
> OBJ, NAME, CYL > OBJ, POSITION, xposcyl, yposcyl, zposcyl > OBJ, SIZE, xsizcyl, ysizcyl, zsizcyl > OBJ, GEOMETRY, cylinder > OBJ, ROTATION24, 1 > OBJ, TYPE, BLOCKAGE > OBJ, MATERIAL, 198,Solid with smooth-wall frictionthe presence of the new object will be recognised by the following lines in Q1EAR:
SPEDAT(SET,CYL,DATFILE,C,cylinder) SPEDAT(SET,OBJNAM,^OB3,C,CYL) SPEDAT(SET,OBJTYP,^OB3,C,BLOCKAGE) SPEDAT(SET,CYL,MATERIAL,R,198.)the following in EARDAT:
CYL DATFILE Ccylinder OBJNAM ^OB3 CCYL OBJTYP ^OB3 CBLOCKAGE CYL MATERIAL R198.and the following in FACETDAT:
OBJECT= 3 NFACETS= 300 OBJNAM = CYL IOBJTYP = 7 OBJCLASS = VOL-OBJECTA distinction should be observed however between these two examples, namely:
-------------- Command ----------------
QCOM(....This command writes anything to the right of the left parenthesis to COPYQ1, which can later be dumped to the Q1 file.
For example, QCOM(BFC=T will write the line: BFC=T to COPYQ1, and QCOM(SOLUTN(P1,Y,Y,Y,Y,Y,Y) will write the line: SOLUTN(P1,Y,Y,Y,Y,Y,Y) to COPYQ1.
However, QCOM does not cause the SATELLITE to interpret what is written to COPYQ1, for example, QCOM(BFC=T will not set BFC to TRUE.
See also DCOM, NOCOPY, NOCOMM.
The Q-criterion [1,2] is popular in the CFD community as a useful criterion for detecting vortices. The Q value is defined as the relative difference between the magnitude of the rate of rotation and strain tensors (and is the second invariant of the rate of deformation tensor). Therefore,Q = 1/2(ΩijΩij - SijSij)
where Ωij and Sij are the magnitudes of the mean rotation and rate of strain tensors, respectively:Ωij = 1/2(∂ui/∂xj-∂uj/∂xi)
andSij = 1/2(∂ui/∂xj+∂uj/∂xi)
The rotation tensor is related to the vorticity tensor ωij byΩij=1/2ωij
and the tensors Ωij and Sij are the antisymmetric and symmetric parts of the deformation tensor
Dij= ∂ui/∂xj = Sij + Ωij.
Hunt et al  defined a vortex as a spatial region where Q > 0, which means where the vorticity tensor dominates the rate of strain tensor. Locations in the flow with positive Q values are defined as vortices using this criterion, as they contain local rotational motion.
In the post-processor the idea is to visualise vortices by generating isosurfaces of Q for several positive values. The recommendation is to use an isosurface at a positive value near zero. Some adjustment will then be required to find the right value to see the vortices.
The Q-criterion can be stored and written to the RESULT and solution files by putting STORE(QCR1) into the Q1 file. For two-phase applications, STORE(QCR2) elicits storage and printout of the Q-criterion for the 2nd phase.
At present it is necessary to also necessary store the mean rates of strain GEN1 and GEN2, and the vorticity magnitudes VOR1 and VOR2. The latter require storage of all ij-velocity derivatives excepting i=j, i.e:
For turbulent flow, usually storage of GEN1 & GEN2 is provided automatically by the turbulence model.
See COVAL for information about how to create patches which provide sources which are proportional (VAlue - Phi) **2
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