AUTOPLOT USE
  file
  phi 5
 
  da 1
  p1
  screen
  msg pressure after 1s
  pl 1
  msg press  to continue
  pause
  cl
  da 1
  u1
  screen
  msg 1st-phase velocity after 1s
  pl 1
  msg press  to continue
  pause
  cl
  da 1
  u2
  screen
  msg 2nd-phase velocity after 1s
  pl 1
  msg press  to continue
  pause
  cl
  da 1
  r1
  screen
  msg 1st-phase volume fraction after 1s
  pl 1
  msg press  to continue
  pause
  cl
  da 1
  r2
  screen
  msg 2nd-phase volume fraction after 1s
  pl 1
  msg press e to END
  enduse
 
    GROUP 1. Run title
TEXT(Kelvin-Helmholtz instability :    W903
TITLE
  DISPLAY
  In the following PHOENICS input file, the single-wave formulation
  is exemplified. The initial volume-fraction profile is made up
  of two straight lines; and the two fluids, of equal densities
  are given equal and opposite velocities. The predicted profiles
  certainly show that the irregularity of the profile increases
  in amplitude.
 
  A 1-second period is considered, divided into 100 equal intervals
  a duct of 1m length is considered, with 20 equal intervals.
  The initial velocities are 1.0 m/s, in opposite directions.
  The initial values of r represent a symmetrical shallow roof
  (or trough).
  The cyclic boundary condition is activated.
  
  PHOTON (Autoplot) commands are provided at the top of the Q1 file.
  ENDDIS
    GROUP 2. Transience; time-step specification
STEADY=F
GRDPWR(T,100,1.0,1.0)
    GROUP 3. X-direction grid specification
GRDPWR(X,20,1.0,1.0)
    GROUP 7. Variables stored, solved & named
ONEPHS=F
SOLVE(P1,U1,U2,R1,R2)
    GROUP 9. Properties of the medium (or media)
  In this run the densities of the two phases are equal.
RHO1=1.0;RHO2=1.0
    GROUP 11. Initialization of variable or porosity fields
FIINIT(U1)=1.0;FIINIT(U2)=-1.0
FIINIT(R1)=0.495;FIINIT(R2)=0.505
INIADD=T
PATCH(INIT1,LINVLX,1,NX,1,1,1,1,1,1)
COVAL(INIT1,R1,0.02,0.0);COVAL(INIT1,R2,-0.02,0.0)
PATCH(INIT2,LINVLX,1+NX/2,NX,1,1,1,1,1,1)
INIT(INIT2,R1,-0.04,0.0);INIT(INIT2,R2,0.04,0.0)
    GROUP 13. Boundary conditions and special sources
XCYCLE=T
  ** Gravitational force
PATCH(LATG,RGRAD,1,NX,1,1,1,1,1,LSTEP)
  The next statement, being displaced to the right, does NOT
  activate the gravity momentum source.
  COVAL(LATG,U2,0.0,100.0)
  ** Relief valve
PATCH(RELIEF,CELL,NX,NX,1,1,1,1,1,LSTEP)
COVAL(RELIEF,P1,FIXP,0.0)
    GROUP 16. Termination of iterations
LSWEEP=25;RESREF(P1)=1.E-5;RESREF(U1)=1.E-5;RESREF(U2)=1.E-5
RESREF(R1)=1.E-5;RESREF(R2)=1.E-5
    GROUP 17. Under-relaxation devices
RELAX(U1,FALSDT,0.01);RELAX(U2,FALSDT,0.01)
RELAX(R1,LINRLX,0.2);RELAX(R2,LINRLX,0.2)
SPEDAT(SET,GXMONI,TRANSIENT,L,F)
    GROUP 21. Print-out of variables
OUTPUT(R1,N,N,N,N,N,N)
    GROUP 22. Spot-value print-out
TSTSWP=-1
    GROUP 23. Field print-out and plot control
NXPRIN=NX/20;IPLTL=LSWEEP;NTPRIN=LSTEP/10
PATCH(LONGPLOT,PROFIL,1,NX,1,1,1,1,1,LSTEP)
PLOT(LONGPLOT,P1,0.0,0.0);PLOT(LONGPLOT,R1,0.0,0.0)
    GROUP 24. Dumps for restarts