TEXT(2D Subsonic Turbulent Round Jet TITLE DISPLAY The problem considered is the near-field of a subsonic turbulent round jet issuing into stagnant surroundings at Mach 0.95. The stagnation enthalpy of the nozzle fluid is equal to that of the free stream, so that with the assumption of unit Prandtl numbers the energy equation need not be solved. The k-e model is used and the calculations are started at the jet discharge plane. The parabolic marching integration is carried out until about 10 diameters downstream. The calculations are made with 30 radial grid cells and a forward step size of 5% (DZW1) of the local grid width. The radial width of the grid increases linearly with downstream distance so as to accommodate the jet spread. ENDDIS So as to allow a direct computation of dimensionless flow variables, the flow equations are normalised such that the flow variables can be interpreted as: P/Po; RHO/RHOo; T/To; U/Uref; H/Href; KE/Uref**2; EP*L/Uref**3; and ENUT/(Uref*L). Here: Po, RHOo and To are the inlet total pressure, density and temperature; Uref=Ao/SQRT(GAMMA); L is the nozzle diameter; and Href=(gam-1.)*Ho/gam, where Ho is the inlet total enthalpy and gam is the specific heat ratio. Ao is the acoustic velocity at To (see Palacio et al, Int.J.Heat Mass Transfer, Vol.33, No.6, p1193, [1990] ). PHOTON USE P PARPHI vec x 1 sh pau;cl con mach x 1 fi;.1 pau;cl con enut x 1 fi;.1 pau cl; con tmp1 x 1 fi;.1 ENDUSE REAL(AIN,CP,GAM,GM1,PTOT,HTOT,RHTOT,PAMB,HAMB,MIN,PIN,HIN,RHOIN) REAL(WIN,EPSIN,TKEIN,DTF,DN,RAD,PRAT,RCON,RGAM,TTOT,TIN,UAC) REAL(FLOWIN,AOIN,UREF,DYGDZ);CHAR(CTURB);BOOLEAN(GEXPAN) ** GEXPAN=T activates a linear y-grid expansion with z GEXPAN=T ** Gas properties GAM=1.4;GM1=GAM-1.;RCON=1.0;CP=RCON*GAM/GM1;RGAM=1./GAM ** INLET CONDITIONS & NOZZLE DIAMETER PTOT=1.0;RHTOT=1.0;TTOT=1.0;MIN=0.95;DN=1.0 HTOT=CP*TTOT RAD=0.5*DN PIN=PTOT/(1.+GM1*MIN*MIN/2.)**(GAM/GM1) RHOIN=RHTOT*(PIN/PTOT)**RGAM;WIN=MIN*(GAM*PIN/RHOIN)**0.5 TIN=PIN/(RCON*RHOIN);HIN=CP*TIN AOIN=(GAM*PTOT/RHTOT)*0.5;UREF=AOIN/GAM**0.5 ** Set static pressure ratio, i.e. PIN/PAMB PRAT=1.0 ** Ambient pressure PAMB=PIN/PRAT;HAMB=HTOT GROUP 1. Run title and other preliminaries GROUP 2. Transience; time-step specification PARAB=T GROUP 3. X-direction grid specification CARTES=F;XULAST=0.1;AIN=0.5*XULAST*RAD*RAD GROUP 4. Y-direction grid specification NY=30;YVLAST=DN;NREGY=2 IF(GEXPAN) THEN + DYGDZ=0.085*1.5;AZYV=1.0;ZWADD=DN/DYGDZ ENDIF IREGY=1;GRDPWR(Y,20,RAD,1.0);IREGY=2;GRDPWR(Y,10,RAD,1.3) GROUP 5. Z-direction grid specification NZ=140;AZDZ=PROPY;DZW1=0.05 GROUP 6. Body-fitted coordinates or grid distortion GROUP 7. Variables stored, solved & named SOLVE(P1,V1,W1) SOLUTN(W1,P,P,P,P,P,N);SOLUTN(V1,P,P,P,P,P,N) ** Provide storage for the density. STORE(RHO1,MACH,ENUT,LEN1,H1,TMP1) TURMOD(KEMODL) GROUP 8. Terms (in differential equations) & devices DENPCO=T ** improve accuracy by accounting for grid inclination in calculation of radial convection fluxes IF(GEXPAN) THEN + V1AD=GRND1 ENDIF GROUP 9. Properties of the medium (or media) RHO1=IDEALGAS;RHO1B=1./RCON;PRESS0=0.0 DRH1DP=IDEALGAS;RHO1C=RGAM TMP1=VARSTAGH;CP1=CP ENUL=1.8E-5/(UREF*DN) GROUP 10. Inter-phase-transfer processes and properties GROUP 11. Initialization of variable or porosity fields TKEIN=(0.1*WIN)**2;EPSIN=0.1643*TKEIN**1.5/(0.1*RAD/DN) FIINIT(EP)=EPSIN; FIINIT(KE)=TKEIN FIINIT(W1)=WIN;FIINIT(RHO1)=RHOIN;FIINIT(P1)=PIN FIINIT(H1)=HTOT INIADD=F PATCH(INITFS,INIVAL,1,1,#2,#2,1,1,1,1) COVAL(INITFS,W1,0.0,0.0) GROUP 13. Boundary conditions and special sources INLET(IN,LOW,1,NX,#1,#1,1,1,1,1) VALUE(IN,P1,RHOIN*WIN);VALUE(IN,W1,WIN) VALUE(IN,KE,TKEIN);VALUE(IN,EP,EPSIN) PATCH(NB,NORTH,1,1,NY,NY,1,NZ,1,1) COVAL(NB,P1,1.E3,PAMB);COVAL(NB,W1,ONLYMS,0.0) GROUP 16. Termination of iterations FLOWIN=RHOIN*WIN*AIN SELREF=F;RESREF(P1)=1.E-12*FLOWIN RESREF(W1)=1.E-12*FLOWIN*WIN RESREF(KE)=1.E-12*FLOWIN*TKEIN;RESREF(EP)=1.E-12*FLOWIN*EPSIN RESREF(V1)=RESREF(W1) GROUP 17. Under-relaxation devices DTF=10.*DZW1*YVLAST/(WIN+UAC) RELAX(V1,FALSDT,DTF);RELAX(W1,FALSDT,DTF) RELAX(KE,LINRLX,0.2);RELAX(EP,LINRLX,0.2);KELIN=3 RELAX(P1,LINRLX,0.15);RELAX(RHO1,LINRLX,0.05) GROUP 18. Limits on variables or increments to them VARMIN(W1)=1.E-10 VARMIN(RHO1)=1.0E-4*RHTOT;VARMIN(H1)=1.0E-10 VARMAX(RHO1)=5.0*RHTOT;VARMAX(H1)=HTOT;VARMAX(P1)=5.0*PTOT GROUP 19. Data communicated by satellite to GROUND GROUP 20. Preliminary print-out GROUP 21. Print-out of variables GROUP 22. Spot-value print-out IXMON=1;IYMON=20;IZMON=1 GROUP 23. Field print-out and plot control ITABL=2;NPLT=5;NYPRIN=2;NZPRIN=NZ/5 IF(NZ.GT.1) THEN + IDISPA=2;IDISPB=1;IDISPC=NZ ENDIF IPARAB=1 LITHYD=60;TSTSWP=-1;IPLTL=LITHYD