TEXT(GXTIM Example TITLE DISPLAY This case demonstrates the use of GXTIM to provide 3 types of periodic sources (in this case for pressure) Gas enters the domain at 'top', with a variable pressure based on the settings of CASENO and PTYPE defined below. top __________________________/\___________________________ /______ ______ ______ ______ ______ ______ ______ ______\ | | | | | | | | | | | pfix | | | | | | | |______|______|______|______|______|______|______|______| IY --> NY=20 ENDDIS CASENO Selects flow type. 0 Gas moving with constant velocity, no entry from top. 1 Gas at rest, sudden sustained entry from top (over all 5 seconds) 2 Gas at rest, intermittent entry from top. (from 1.25 seconds onwards) 3 As for 2, with pressure=press0 at NY/4. INTEGER(CASENO);CASENO=3 PTYPE Selects the way in which the pressure (at top) behaves over time. It is only relevant for CASENO = 2 or 3. _ _ _ 1 Battlement, ie |_| |_| |_ 2 Saw-tooth, ie \/\/\/\/\/\ 3 Sine curve. INTEGER(PTYPE);PTYPE=3 TIMA = Wave amplitude ITIMA = number of time steps for a complete cycle ITIMB = first time step at which the patch is active ITIMC = last time step at which the patch is active Other model constants. REAL(VIN,WIN,TIN,PIN,GASCONST,HIN,CP,CV,GAMMA,FLOIN) GASCONST=1.0;GAMMA=1.4;CV=GASCONST/(GAMMA-1.0);CP=CV*GAMMA VIN=0.0;TIN=1.0;HIN=CP*TIN;PIN=0.0 For CASENO=0, set the gas velocity. IF(CASENO.EQ.0) THEN + VIN=0.5 ENDIF GROUP 4. Y-direction grid specification GRDPWR(Y,20,1.0,1.0) GROUP 5. Z-direction grid specification STEADY=F;LSTEP=500;GRDPWR(T,LSTEP,5.0,1.0) GROUP 7. Variables stored, solved & named SOLVE(P1,V1,H1) GROUP 9. Properties of the medium (or media) RHO1=IDEALGAS;RHO1A=0.0;RHO1B=1.0;PRESS0=1.0;RHO1C=0.0 DRH1DP=RHO1B;TMP1=LINH;TMP1B=1.0/CP;CP1=CP GROUP 11. Initialization of variable or porosity fields FIINIT(P1)=PIN;FIINIT(V1)=VIN;FIINIT(H1)=HIN GROUP 13. Boundary conditions and special sources Initially set the wave to act over all time steps ITIMB=0;ITIMC=LSTEP For CASENO=1, there is a sudden sustained entry of gas from the top IF(CASENO.EQ.1) THEN + FLOIN=0.5 + PATCH(TIMTOP,NORTH,1,1,NY,NY,1,1,1,LSTEP) + COVAL(TIMTOP,P1,FIXFLU,GRND1) + COVAL(TIMTOP,V1,ONLYMS,-FLOIN) + COVAL(TIMTOP,H1,ONLYMS,4*HIN) + TIMA=FLOIN;ITIMA=2*LSTEP ENDIF For CASENO=2 or 3, there is a variable entry of gas from the top (dependent on the value of PTYPE) over all time steps. IF((CASENO.EQ.2).OR.(CASENO.EQ.3)) THEN + FLOIN=0.1 + REAL(ARG) + CASE PTYPE OF + WHEN 1 Battlement + ARG=GRND1 + WHEN 2 Saw-tooth + ARG=GRND2 + WHEN 3 Sine wave + ARG=GRND3 + ORELSE Battlement + ARG=GRND1 + ENDCASE + PATCH(TIMTOP,NORTH,1,1,NY,NY,1,1,1,LSTEP) + COVAL(TIMTOP,P1,FIXFLU,ARG) + COVAL(TIMTOP,V1,ONLYMS,-FLOIN) + COVAL(TIMTOP,H1,ONLYMS,4*HIN) + TIMA=FLOIN;ITIMA=LSTEP/4 ENDIF For CASENO=3, set the pressure at NY/4 IF(CASENO.EQ.3) THEN + PATCH(PFIX,CELL,1,1,NY/4,NY/4,1,NZ,1,1) + COVAL(PFIX,P1,7.5E-4,0.0) + COVAL(PFIX,V1,ONLYMS,VIN) + COVAL(PFIX,H1,ONLYMS,HIN) ENDIF GROUP 16. Termination of iterations LSWEEP=10;SELREF=T;RESFAC=1.E-2;VARMIN(H1)=0.5 GROUP 19. Data communicated by satellite to GROUND GROUP 22. Spot-value print-out IXMON=1;IYMON=1 GROUP 23. Field print-out and plot control TSTSWP=LSWEEP;ITABL=1;NYPRIN=1;NTPRIN=LSTEP/4 IDISPA=10;IDISPB=1;IDISPC=LSTEP PATCH(PROFILES,PROFIL,1,1,1,NY,1,NZ,1,1) PLOT(PROFILES,P1,0.0,0.0);PLOT(PROFILES,V1,0.0,0.0) PLOT(PROFILES,H1,0.0,0.0)