GROUP 1. Run title and other preliminaries TEXT(Case 1 AXI-Symmetric Piston Bowl TITLE DISPLAY A piston with a flat crown having an open cavity with a central cusp moves inside a flat topped cylinder. The solution domain is represented by a 2-part moving grid, the first part of which expands and contracts in the Z-direction. The second part of the grid moves with the piston, but does not change its size. This part of the grid includes the piston cavity, which is represented by porosities. Since the model simulates only the compression and expansion parts of the four-stroke cycle, there are no inflow or outflow boundaries. The flow is represented in two-dimensional axi-symmetric polar coordinates in the Y-Z plane but with swirl velocity in the X-direction. An initial field of U-velocity is set up to represent 'solid body' rotation of the fluid. The density varies isentropically with pressure. This is based on the PHOENICS-81 PDR/CHAM UK/6. ENDDIS REAL(RPS,PI ,A1,AN,ANGLE,DEGS);RPS=24.0;PI=3.1416;A1=1.0 AN=291.;ANGLE=AN-A1;DEGS=RPS*360. GROUP 2. Transience; time-step specification STEADY=F;TFIRST=A1/DEGS;TLAST=AN/DEGS;LSTEP=10 TFRAC(1)=-7.;TFRAC(2)=10./ANGLE;TFRAC(3)=18.0;TFRAC(4)=5./ANGLE TFRAC(5)=40.;TFRAC(6)=1./ANGLE;TFRAC(7)=4.;TFRAC(8)=5./ANGLE TFRAC(9)=7.;TFRAC(10)=10.0/ANGLE GROUP 3. X-direction grid specification CARTES=F;XULAST=.1 GROUP 4. Y-direction grid specification NY=11;YFRAC(1)=0.073;YFRAC(2)=0.145;YFRAC(3)=0.218;YFRAC(4)=0.29 YFRAC(5)=0.363;YFRAC(6)=0.421;YFRAC(7)=0.458;YFRAC(8)=0.508 YFRAC(9)=0.653;YFRAC(10)=0.753;YFRAC(11)=0.88632;YVLAST=0.0689 GROUP 5. Z-direction grid specification ** Grid specified at BDC. NZ=11;ZWLAST=0.1707;ZFRAC(1)=0.227;ZFRAC(2)=0.518;ZFRAC(3)=0.673 ZFRAC(4)=0.776;ZFRAC(5)=0.825;ZFRAC(6)=0.853;ZFRAC(7)=0.882 ZFRAC(8)=0.926;ZFRAC(9)=0.953;ZFRAC(10)=0.982;ZFRAC(11)=1.0 GROUP 7. Variables stored, solved & named SOLVE(P1,U1,V1,W1);SOLUTN(P1,Y,Y,Y,N,N,N) GROUP 9. Properties of the medium (or media) ENUL=1.E-5;ENUT=1.E-1;RHO1=COMPRESS;DRH1DP=COMPRESS;RHO1A=1.4839E-4 RHO1B=0.765;PRESS0=1.03E5 GROUP 11. Initialization of variable or porosity fields ** Angular velocity for solid body rotation U/R=CONST. IURINI=-1;FIINIT(U1)=407.13 ** Piston crown CONPOR(0.0,VOLUME,1,1,-8,NY,-6,NZ) GROUP 13. Boundary conditions and special sources ** Cylinder head WALL (HEAD,LOW,1,1,1,NY,1,1,1,LSTEP) ** Cylinder wall WALL (WALL,NORTH,1,1,NY,NY,1,5,1,LSTEP) GROUP 15. Termination of sweeps LSWEEP=20 GROUP 16. Termination of iterations LITER(P1)=10 GROUP 17. Under-relaxation devices RELAX(V1,FALSDT,1.E-1);RELAX(W1,FALSDT,1.E-1) GROUP 18. Limits on variables or increments to them VARMIN(P1)=5.E4 GROUP 19. Special calls from EARTH to GROUND ** Specifications of moving grid W1AD=ZMOVE ** Set 2nd part grid IZW1=5 ** Angular velocity AZW1=150.796 ** Crank radius BZW1=.06985 ** Conrod centre distance/crank radius CZW1=3.7265 SPEDAT(SET,GXMONI,TRANSIENT,L,F) GROUP 22. Spot-value print-out IXMON=1;IYMON=1;IZMON=5;ITABL=2 GROUP 23. Field print-out and plot control SUBWGR=T PATCH(PROF,PROFIL,1,1,1,NY,3,3,LSTEP,LSTEP) PLOT(PROF,U1,0.,0.);PLOT(PROF,W1,0.0,0.0);PLOT(PROF,V1,0.0,0.0) PATCH(CONT,CONTUR,1,1,1,NY,1,NZ,LSTEP,LSTEP) PLOT(CONT,W1,0.,20.);PLOT(CONT,U1,0.,20.)