!--Base SI units are employed throughout the program
!--Different units may be used in the input and output
!
!--Variables in data file DS2VD.DAT
!
!--uncommented data items are those in versions 3.1 and 3.2
!
!--NVER the n in version n.m that generated the data file
!--MVER the m in version n.m that generated the data file
!
!--m must change whenever the data file is altered
!
!--MMEG the approximate number of megabytes that are available to the calculation
!
!--IFX 0,1 for two-dimensional, axially-symmetric flow
!--IWF 0,1 no, yes for radial weighting factors (IFX=1 only)
!--XMIN the minimum x coordinate of the bounding rectangle
!--XMAX the maximum x coordinate of the bounding rectangle
!--YMIN the minimum y coordinate of the bounding rectangle
!--YMAX the maximum y coordinate of the bounding rectangle
!--FRACF the approximate fraction of the rectangle that is occupied by flow
!--the following item was introduced in version 3.4
!--AVDEN an estimate of the ratio of the average density to the reference density
!
!--MSP number of molecular species
!--MMVM maximum number of vibrational modes of any species
!--MNRE the number of gas phase reactions
!--MTBP (required only if MNRE>0) the number of third-body probability
! tables for recombinations
!--MNSR the number of surface reactions
!--in a loop (N) over MSP
!----SP(1,N) the reference diameter
!----SP(2,N) the reference temperature
!----SP(3,N) the viscosity temperature power law
!----SP(4,N) reciprocal of the VSS scattering parameter (Unity for the VHS model)
!----SP(5,N) the molecular mass
!----SPTEXT(N) character description (NVER > 3 only)
!----ISPR(3,N) the electric charge (NVER > 3 and MVER > 1 only)
!----ISPR(1,N) the number of rotational degrees of freedom
!----if ISPR(1,N) > 0
!------ISPR(2,N) 0,1 for constant or polynomial rotational relaxation number
!------SPR(1,N) the constant rotational relaxation collision number, or the
! constant in the second order polynomial in temperature
!------if ISPR(2,N) > 0
!--------SPR(2,N) the coefficient of temperature in the polynomial
!--------SPR(3,N) the coefficient of the square of temperature in the polynomial
!------end if
!------if MMVM > 0
!--------ISPV(N) the number of vibrational modes
!--------in a loop (K) over ISPV(N) (if ISPV(N) > 0)
!----------SPV(K,N) the characteristic vibrational temperature
!----------SPVM(1,K,N) constant Zv, or reference Zv for mode K
!----------SPVM(2,K,N) -1. for constant Zv, or reference temperature
!---the following three items are for (NVER > 3 and MVER > 4 only) (above were C1 and C2 before this)
!----------SPVM(3,K,N) the characteristic dissociation temperature
!----------ISPVM(1,K,N) the code of the first post-dissociation molecule
!----------ISPVM(2,K,N) the code of the second post-dissociation molecule
!
!--------end of loop
!------end if
!----end if
!--end of loop
!
!--if MNRE > 0
!----in a loop (K) over MNRE
!------RETEXT(K) character description (NVER > 3 and MVER > 1 only)
!------IRET(K) type of reaction (NVER > 3 and MVER > 4 only)
! 0 not yet classified, 1 dissociation, 2 recombination, 3 forward exchange, 5 reverse exchange
!------LE(K) the species code of the first molecule
!------ME(K) the species code of the second molecule, or -1 if the collision is with the linked electron,
!------but set species code to -1 if an electron is an independent collision partner
!------for three post-collision particles
!--------KP(K) the first post-reaction species code
!--------LP(K) the second post-reaction species code
!--------MP(K) the third post-reaction species code
!------for one post-collision particle
!--------KP(K)=-1
!--------LP(K) the species code of the molecule
!--------MP(K) if positive the code of the third body in a recombination
! or, if negative, the code of the third-body table
! or zero for an ion and linked electron
!------for two post-collision particles
!--------KP(K)=0
!--------LP(K) the first post-reaction species code
!--------MP(K) the second post-reaction species code
!------CI(K) the number of internal degrees of freedom that contribute
!------AE(K) the activation energy for the reaction
!------AC(K) 1.E10 times the pre-exponential parameter
!------BC(K) the temperature exponent in the rate equation
!------ER(K) the energy of the reaction
!----end of loop
!----in a loop (J) over MTBP
!------in a loop (L) over MSP
!--------THBP(J,L) the relative efficiency in recombinations
!------end of loop
!----end of loop
!--end if
!
!--if MNSR > 0
!----in a loop (K) over MNSR
!------SRETEXT(K) character description (NVER > 3 and MVER > 1 only)
!------LIS(1,K) the species code of the first incident molecule
!------LIS(2,K) the species code of the second incident molecule (0 if none)
!------LRS(1,K) the species code of the first reflected molecule
!------LRS(2,K) the species code of the second reflected molecule (0 if none)
!------LRS(3,K) the species code of the third reflected molecule (0 if none)
!------LRS(4,K) the species code of the fourth reflected molecule (0 if none)
!------LRS(5,K) the species code of the fifth reflected molecule (0 if none)
!------LRS(6,K) the species code of the sixth reflected molecule (0 if none)
!------ERS(K) the energy of the reaction (+ve for recombination, -ve for dissociation)
!----end of loop
!--end if
!
!--FND the number density of the stream or reference gas
!--FTMP temperature of stream or reference gas
!--IF (MMVM > 0)
!----VTREF vibrational temperature in stream or reference gas
!--END IF
!--VFX the velocity component in the x direction
!--if IFX=0
!----VFY the velocity component in the y direction
!----VFZ the velocity component in the z direction
!--end if
!--in a loop over the number of species
!----FSP(N) the fraction of species N in the stream or reference gas
!--end of loop
!
!--NSURF the number of unconnected surfaces
! (the initial and final points must be coincident for a closed surface
! or must lie on a flow boundary in the case of an open surface)
! (The outside boundary of the flow is defined by combinations of
! stream boundaries, open surfaces, planes of symmetry etc. and
! the geometry must be such that there is only one such boundary.)
!
!--in a loop (N) over NSURF
!----NPOINT(N) the number of points on the surface (number of intervals + 1)
!--end loop
!--MPOINT the maximum number on any surface
!--MSGROUP the maximum number of surface groups
!--MSSLG the maximum number of solid surface intervals
!--MESLG the maximum number of molecule entry intervals
!
!--in a loop (N) over NSURF (implicit arrays are in order of surface,group,species (as many as needed))
!----LSEG the number of (straight or arc) segments on line N
!----in a loop (M) over LSEG
!------KSEG 1 for a straight line segment
! 2 for an arc of a circle in a clockwise direction
! -2 for an arc of a circle in an anti-clockwise direction
!------XCEN, YCEN the coordinates of the center (arc only) (MUST HAVE ONLY ONE DATA ITEM PER LINE)
!------XI,YI the coordinates of the initial point (M=1 only)
!------XF,YF the coordinates of the final point
! (the point ordering is such that the flow is to the right of the segment
! joining XI,YI to XF,YF, both sides of a thin surface must be defined)
!------NPSEG the number of sampling intervals along this segment
!----end of loop over LSEG
!----NGROUP the number of groups of data on this surface
!----loop over the NGROUP groups of surface intervals
!------LINTG the number of intervals within the group
!------ITYPS 1 if the group is a solid surface with species independent properties
! 2 if it is a solid surface with species dependent properties
! (an outgassing surface must be type 2)
! 3 if it is a gas entry boundary with specified properties
! 4 if it is a stream entry interval
!------if ITYPS = 1 or 2 (solid surface boundary)
!--------TSURF if +ve, fixed surface temperature for diffuse or CLL reflection
! if -ve,diffuse or CLL adiabatic insulated with the absolute value as the minimum temperature
! if 0.0 generates the temperature of a perfectly (thermal) conducting surface that extends for the interval
! if diffuse adiabatic (-ve or 0.0 TSURF)
!----------EMISS the surface emissivity
! end if
!--------VSURFI in-plane velocity of surface
!--------VSURFN normal-to-plane velocity of two-dimensional surface, or
! angular velocity of surface in an axially symmetric flow
!--------in a loop (K) over 1 for ITYPS=1 or the number of species MSP for ITYPS=2
!----------IRFM(K) 0,1 for diffuse, CLL model
!----------if IRFM(K) = 1
!------------EACN(K) the normal energy accommodation coefficient
!------------TMAC(K) the tangential momentum accommodation coefficient
!----------end if
!----------ROTAC(K) rotational accommodation coefficient
!----------if MMVM > 0
!------------VIBAC(K) vibrational accommodation coefficient
!----------end if
!----------FRSPEC(K) fraction specular
!----------FRSORB(K) fraction adsorbed
!----------if ITYPS = 2 OUTGMF(K) the outgas mass flux
!--------end of loop over 1 or MSP
!--------if MNSR > 0
!----------in a loop (K) over the number of surface reactions MNSR
!------------PROBSR(K) the probability of the surface reaction
!----------end of loop over MNSR
!--------end if
!------end if
!------if ITYPS = 3 (specified gas entry boundary)
!--------XVEL the velocity component in the x or axial direction
!--------YVEL the velocity component in the y direction
!--------ZVEL the velocity component in the z direction
!--------EFTMP the flow temperature
!--------EFDEN the number density of the flow
!--------in a loop over the number of species L=1,MSP
!----------EFSP(L) the fraction of species L
!--------end of loop over species
! the following three items appear only if NVER = 3 and MVER > 5, or NVER > 3
!--------STSTART the time at which the flow starts
!--------STSTOP the time at which the flow stops
!--------NSTO 0 if the interval group is effectively a vacuum when the stream is off
! 1 if the interval group is effectively a plane of symmetry when the stream is off
! end if
!----end loop over the groups of intervals
!--end loop over surfaces
!
!--in a loop (N), 1 for XMIN, 2 for XMAX, 3 for YMIN, and 4 for YMAX
!----ITB(1) 1 for an axis (axially symmetric flows only)
! 2 for a plane of symmetry
! 3 for an interface with the uniform freestream
! 4 for a vacuum
! 5 for periodic boundaries (N=1 or 2 only, and must apply to both)
! 6 for constant pressure boundaries (N=1 or 2 only, and must apply to both)
! and has mass flux fixed by the flux across x=CSSB
! 7 for a plane, cylindrical or spherical specular boundary that moves into the flow at a constant speed
! (N=1 only, and the surface starts moving from x=XMIN)
! 8 if the boundary is not in the flow
!--end loop
!
!--if ITB(1)=7
!----ITB(3) and ITB(4) must be planes of symmetry (or axis) if the absolute value of the center > 1.E8 (plane piston)
! For finite piston center, axis plane of symmetry and/or specularly reflecting surfaces must pass through the center.
! spherical (axi sym) with center at the point at which the sides intersect
!----VWALL the speed of the moving wall (must be +ve)
!--the following two items appear only if NVER=4 and MVER>2, or MVER>4
!----TSWALL the time at which piston motion stops
!----CWALL the x coordinate of the center of the piston which must be at y=0
!--end if
!
!--IFILL 1 if the initial flow is the stream (the secondary stream is employed
! above or beyond CSSB if ISSB == 1), or
! 2 if the flowfield is initially a vacuum
!
!--the following item appears only if NVER = 3 and MVER > 6, or NVER > 3
!----IFILENT 0 if there are no file entry molecules, or 1 if there are
!--the following two items only if NVER>3 and IFILENT=1
!--NMIF number of molecules in each record
!--NOIF number of records in file
!
!--ISSB 0 if an initial flow state separation boundary is not set, or
! 1 if the initial state consists of the stream and secondary stream
! separated at a line of constant x
! -1 if the separation is at a line of constant y
!--if ISSB=1 or -1
!----CSSB the coordinate of the flow separation boundary
!----FNDA number density of secondary stream or reference gas
!----FTMPA temperature of secondary stream or reference gas
!----VFXA the velocity component in the x direction of the secondary stream
!----VFYA the velocity component in the y direction
!----in a loop over the number of species
!------FSPA(N) the fraction of species N in the stream or reference gas
!----end of loop
!--end if
!
!--ISF 0,1 for unsteady, steady flow sampling
!
!--ISO 0,1 for standard,custom options (custom options for experienced users only)
!--if ISO = 1 then
!----if (IFX=1 and IWF=1) RWF the reference value of the weighting factor
! the weighting factor is 1+RWF*(Y/YMAX) (standard is 10000.)
!----FDIVS factor to change the standard number of divisions in the x & y directions
!----NELX the number of elements in each division in the x & y directionS (standard is 10)
!----FINM factor to change the initial number of molecules
! (default sets molecules to 0.4 the maximum number based on nominated memory)
!----MIMCT number of moves in a mean collision time (standard is 5)
!----MIMTT number of moves in mean transit time (standard is 2)
!----FTIMS factor to change the standard sampling interval
!----FTIMO factor to change the standard output interval
!----FTOS (ISF =0 only) the fraction of the sampling interval over which a time sample is taken (default is 0.5)
!----FDDB (IFX=1) the factor to change the size of the duplication delay buffer
!----JCI 0 if reactions are based on rate equations
! 1 if reactions are based on collision events
!----JRR 0 to retain default relaxation rates based on the overall gas temperature (REMOVED 3.8 and above)
! 1 to base the relaxation rates on the "collision temperature"
!----JNN is in data only if NVER = 3 and MVER > 2, or NVER >3
!------JNN 0 to employ nearest-neighbor collisions in all cases(also see ITSC)
! 1 to not employ nearest neigbor collisions when there are radial weigh factors
!
!--end if