PHOTON USE
  p
  parphi
 
 
 
 
  msg                        TURBULENT ROUND JET
  msg
  msg        Velocity vectors:
  vec x 1 sh
  msg            -
  msg Press  to continue
  pause
  vec off;red
  msg        Axial velocity contours:
  con wcrt x 1 fi; 0.01
  msg            -
  msg Press  to continue
  pause
  con off;red
  msg        Temperature contours:
  con temp x 1 fi;0.01
  msg
  msg Press  to continue
  pause
  con off;red
  msg        eddy-viscosity (enut) contours:
  con enut x 1 fi;0.01
  msg
  msg Press e to END
  enduse
 
    GROUP 1. Run title and other preliminaries
TEXT(Round Jet;Mixing Length Model;Para
TITLE
mesg(PC486/50 time last reported as appx. 3.min.
  DISPLAY
  The axi-symmetrical turbulent jet in stagnant surroundings is
  considered. This becomes "self-similar" after an initial
  development length, with the centre-line velocity and temperature
  difference varying as the reciprocal of the longitudinal distance.
 
  In case 153, the Prandtl Mixing-Length model is used, with the
  mixing length proportional to the distance across the jet.
 
  In case 154, the Prandtl Energy model is used, with the same
  presumption about the length scale.
 
  In case 155, the k-epsilon model is used, so that no length-scale
  presumption is needed.
 
  A PHOTON USE file is supplied
  ENDDIS
 
 
   GXLEN and GXENUT are used for this case.
 
    The locally-defined variables are as follows:
 
     WJET     Jet velocity at the inlet                 (m/s)
     REYNO    Reynolds number
     DIAM     The diameter of the jet nozzle            (m)
     TJET     The jet temperature at the inlet          (C)
     TFREE    The temperature of the free stream        (C)
 
  The experimental data indicate velocity and temperature half-width
  spreading rates of 0.086 and 0.11, respectively, in the self-
  similar region of the jet. The present calculation predicts values
  of 0.083 and 0.099, respectively, which are in very good agreement
  with the experimental values. The sensitivity of the solution to
  grid-size may be assessed by increasing NY and reducing the
  forward step size DZW1 ( and consequently increasing NZ ).
 
 
REAL(WJET,REYNO,DIAM,TJET,TFREE)
REYNO=5.E5;DIAM=0.1;WJET=10.0;TJET=1.0;TFREE=0.0
 
    GROUP 3. X-direction grid specification
CARTES=F;XULAST=0.1
    GROUP 4. Y-direction grid specification
NY=20;YVLAST=DIAM;YFRAC(1)=-20;YFRAC(2)=1.0/20.0
   *** Linear grid expansion of DYGDZ
REAL(DYGDZ);DYGDZ=0.086*2.9
AZYV=1.0;ZWADD=DIAM/DYGDZ
    GROUP 5. Z-direction grid specification
PARAB=T
  ** The change in z-direction step size is supplied
     in group 5 of GROUND by setting AZDZ=PROPY;
     the parameter, DZW1 is set in group 19 below for
     this purpose.
NZ=100;AZDZ=PROPY
    GROUP 7. Variables stored, solved & named
SOLVE(P1,V1,W1,H1);NAME(H1)=TEMP;STORE(ENUT,LEN1)
    GROUP 8. Terms (in differential equations) & devices
DIFCUT=0.0;TERMS(TEMP,N,Y,Y,Y,Y,Y)
 
    GROUP 9. Properties of the medium (or media)
ENUL=WJET*DIAM/REYNO;PRT(TEMP)=0.7
  **Select formula for the length scale supplied in GXLEN by setting
    EL1=MIXLENJET, for which the parameters, EL1A, EL1C, EL2A, EL2B
    are set in group 19.
EL1=MIXLENJET
  **Select Prandtl mixing-length formula supplied in GXENUT for
    the turbulent kinematic viscosity.
ENUT=MIXLEN
    GROUP 13. Boundary conditions and special sources
    1. Outer Boundary-- free stream
PATCH(HIGHY,NORTH,1,1,NY,NY,1,NZ,1,1)
COVAL(HIGHY,P1,1.0E4,0.0);COVAL(HIGHY,W1,ONLYMS,0.0)
COVAL(HIGHY,V1,ONLYMS,0.0);COVAL(HIGHY,TEMP,ONLYMS,TFREE)
    2. Inlet Boundary-- uniform flow
PATCH(NOZZLE,LOW,1,1,1,NY/2,1,1,1,1)
COVAL(NOZZLE,P1,FIXFLU,RHO1*WJET);COVAL(NOZZLE,W1,ONLYMS,WJET)
COVAL(NOZZLE,TEMP,ONLYMS,TJET)
    GROUP 14. Downstream pressure for PARAB=T
IPARAB=1
    GROUP 16. Termination of iterations
SELREF=T;RESFAC=1.E-2;LITHYD=25
    GROUP 17. Under-relaxation devices
RELAX(V1,FALSDT,10.0);RELAX(W1,FALSDT,10.0)
RELAX(TEMP,FALSDT,10.0)
    GROUP 18. Limits on variables or increments to them
VARMIN(V1)=-1.E3;VARMAX(V1)=1.E3
    GROUP 19. Data communicated by SATELLITE to GROUND
  ** Parameter for grid expansion
DZW1=0.1
  ** Select strain-rate for use in Mixing-Length model
DWDY=T
  ** EL1A = mixing-length constant for mixing-layer zone
     EL1B =   ''     ''      ''    for jet zone
     EL1C = velocity fraction for jet-width calculation
     EL1D = free-stream velocity for jet-width calculation
     EL1E = jet-discharge velocity ( mixing-length constant
            is switched from EL1A to EL1B, when centre-line
            velocity falls below EL1E )
EL1A=0.05;EL1B=0.075;EL1C=0.01;EL1D=0.0;EL1E=WJET
    GROUP 22. Monitor print-out
IZMON=NZ/2;IYMON=NY/2;ITABL=1;NPLT=1;IPLTL=LITHYD
TSTSWP=-5;NYPRIN=2
    GROUP 23. Field print-out and plot control
ORSIZ=0.4;PATCH(IZEQNZ,PROFIL,1,1,1,NY,NZ,NZ,1,1)
PLOT(IZEQNZ,W1,0.0,0.0);PLOT(IZEQNZ,TEMP,0.0,0.0)
PLOT(IZEQNZ,ENUT,0.0,0.0)
NZPRIN=NZ
    GROUP 24. Dumps for restarts
IDISPA=1