GROUP 1. Run title and other preliminaries TEXT(Wall Jet K-E Turbu Model; Parab TITLE DISPLAY The application considered is the self-preserving turbulent plane jet. This flow is of interest for many engineering applications including for example, film cooling and heating and ventilating. Here, the wall jet is described as a steady incompressible jet of fluid emanating from a narrow slot and blowing tangentially over a rigid plane adiabatic surface. The injected fluid is heated above the ambient temperature. The flow in a turbulent wall jet can be regarded as that of a wall layer and a free shear layer interacting with each other, and therefore the wall jet is a much more complex flow than say a conventional turbulent boundary layer or a free turbulent jet. ENDDIS Like the free jet (see case 150 for example) the wall jet in stagnant surroundings becomes self-similar after a certain development region. In the wall jet the characteristic scales are the velocity half-width, d, and the maximum velocity, Wm. In the self-similar region, the jet spreads linearly and Wm decays as z**(-m). Here the exponent m must be determined empirically because the constancy of the flux of momentum does not hold in the wall jet. Experiments indicate that m is slightly less than -1/2. Dynamic similarity of the thermal field can be expected, implying a linear growth of the temperature half-width, dt, and a maximum temperature excess which decays as z**-(1+m). Therefore, this temperature excess and Wm can be expected to decay at approximately the same rate. The calculations are started at the jet origin with arbitrary initial profiles; and the calculation extends downstream until self-similarity is attained. The calculations are made with 50 grid nodes across the jet and a forward step size of 10% of the local width. The turbulent Prandtl number is set equal to 0.86 and the molecular Prandtl number to 0.71. The k-e turbulence model is used with the standard set of model constants. This model considerably overpredicts the spreading rate of the jet. To predict correctly the wall-jet development, the model must be extended to account for the wall's damping of the lateral velocity fluctuations. REAL(WFREE,TFREE,TKEIN,EPSIN,GMIXL,WJET,REYNO,HSLOT,TJET,FRA) REYNO=18000.;HSLOT=6.E-3;WJET=54.;TJET=1.0;WFREE=0.0;TFREE=0.0 GROUP 4. Y-direction grid specification NY=50;YVLAST=1.25*HSLOT YFRAC(1)=-1.000E+00;YFRAC(2)=1.200E-02 YFRAC(3)=1.000E+00;YFRAC(4)=3.000E-03 YFRAC(5)=2.000E+00;YFRAC(6)=2.000E-03 YFRAC(7)=2.000E+00;YFRAC(8)=3.000E-03 YFRAC(9)=2.000E+00;YFRAC(10)=3.500E-03 YFRAC(11)=2.000E+00;YFRAC(12)=6.500E-03 YFRAC(13)=2.000E+00;YFRAC(14)=1.000E-02 YFRAC(15)=2.000E+00;YFRAC(16)=1.250E-02 YFRAC(17)=2.000E+00;YFRAC(18)=1.500E-02 YFRAC(19)=4.000E+00;YFRAC(20)=2.000E-02 YFRAC(21)=2.000E+00;YFRAC(22)=2.000E-02 YFRAC(23)=2.000E+01;YFRAC(24)=2.800E-02 YFRAC(25)=8.000E+00;YFRAC(26)=2.500E-02 **Linear Expansion AZYV=1.0 ZWADD=YVLAST(INLET)/DYLDZ DYLDZ=.09*2.5=.2625 AZYV=1.0;ZWADD=3.3333E-2 GROUP 5. Z-direction grid specification NZ=8;AZDZ=PROPY;PARAB=T GROUP 7. Variables stored, solved & named SOLUTN(P1,Y,Y,N,N,N,Y);SOLUTN(V1,Y,Y,N,N,N,Y);SOLUTN(W1,Y,Y,N,N,N,Y) SOLUTN(KE,Y,Y,N,N,N,Y);SOLUTN(EP,Y,Y,N,N,N,Y) NAME(H1)=TEMP;SOLUTN(TEMP,Y,Y,N,N,N,Y) STORE(ENUT);VARMIN(KE)=1.E-10;VARMIN(EP)=1.E-10 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) PRT(TEMP)=0.86;ENUL=WJET*HSLOT/REYNO ** Select Prandtl-Kolmogorov: Group 9/Sect. 5 of GREX3 ** Select k-e Length scale: Group 9/Sect. 12 of GREX3 EL1=KE15DEP;ENUT=PRKOLM GROUP 11. Initialization of variable or porosity fields ** Inside the nozzle The following initializations of the fields at the first forward step are done solely to promote convergence. The inlet conditions are set in Group 13. PATCH(INSIDE,INIVAL,1,1,1,42,1,1,1,1);INIT(INSIDE,W1,0.0,WJET) ** Inlet Intensity of 1% TKEIN=0.0001*WJET*WJET INIT(INSIDE,KE,0.,TKEIN) ** Inlet dissipation rate = .1643*k**1.5/Lm GMIXL=0.035*HSLOT;EPSIN=TKEIN**1.5/GMIXL*.1643 INIT(INSIDE,EP,0.,EPSIN);INIT(INSIDE,TEMP,0.,TJET) ** Outside the nozzle PATCH(OUTSIDE,INIVAL,1,1,43,NY,1,1,1,1) INIT(OUTSIDE,W1,0.,WFREE);INIT(OUTSIDE,TEMP,0.,TFREE) GROUP 13. Boundary conditions and special sources ** Outer Boundary PATCH(OUTER,NORTH,1,1,NY,NY,1,NZ,1,1) COVAL(OUTER,P1,1.E4,0.0);COVAL(OUTER,TEMP,ONLYMS,TFREE) COVAL(OUTER,W1,ONLYMS,0.0);COVAL(OUTER,V1,ONLYMS,0.0) COVAL(OUTER,KE,ONLYMS,1.E-10);COVAL(OUTER,EP,ONLYMS,1.E-5) ** Inlet Boundary PATCH(PROF,LOW,1,1,1,42,1,1,1,1) COVAL(PROF,P1,FIXFLU,WJET);COVAL(PROF,W1,ONLYMS,WJET) ** Inlet Intensity of 1% COVAL(PROF,KE,ONLYMS,TKEIN);COVAL(PROF,EP,ONLYMS,EPSIN) COVAL(PROF,TEMP,ONLYMS,TJET) ** Activate source terms for k and e: Group 13 of GREX3 PATCH(KESO,PHASEM,1,1,1,NY,1,NZ,1,1) COVAL(KESO,KE,KESOURCE,KESOURCE);COVAL(KESO,EP,KESOURCE,KESOURCE) ** Wall-Boundary WALL (WALL1,SOUTH,1,1,1,1,1,NZ,1,1) GROUP 14. Downstream pressure for PARAB=T IPARAB=1 GROUP 16. Termination of iterations LITHYD=20 GROUP 17. Under-relaxation devices RELAX(V1,FALSDT,100.0);RELAX(W1,FALSDT,100.) RELAX(KE,FALSDT,50.0);RELAX(EP,FALSDT,50.) GROUP 19. Data communicated by SATELLITE to GROUND ** Select strain-rate for turbulence production term DWDY=T;FRA=0.05 DZW1=FRA EL1A=0.01;EL1B=WFREE;EL1C=WJET GROUP 21. Print-out of variables OUTPUT(P1,Y,Y,Y,Y,Y,Y);OUTPUT(V1,Y,Y,Y,Y,Y,Y) OUTPUT(W1,Y,Y,Y,Y,Y,Y);OUTPUT(KE,Y,Y,Y,Y,Y,Y) OUTPUT(EP,Y,Y,Y,Y,Y,Y);OUTPUT(TEMP,Y,Y,Y,Y,Y,Y) GROUP 22. Monitor print-out IZMON=1;IYMON=12 GROUP 23. Field print-out and plot control NPLT=2;ITABL=2;IPLTL=40 NYPRIN=2;NZPRIN=2 PATCH(IZEQNZ,PROFIL,1,1,1,NY,1,NZ,1,1) PLOT(IZEQNZ,W1,0.,0.0);PLOT(IZEQNZ,TEMP,0.0,0.0) PLOT(IZEQNZ,KE,0.0,0.0)