#cls text(USP 2D UNSTEADY DIFFUSION PROBLEM title DISPLAY This case solves a two-dimensional transient diffusion problem with time-dependen boundary conditions. The analytical solution is: TEM1 = X + Y + T , where X and Y are cartesian coordinates and T is time. The TEM1 computed by PHOENICS, the exact solution is EXAC. The Q1 contains PHOTON USE commands ENDDIS PHOTON USE p;;;;; con tem1 z 1 fi;0.01 msg Numerical solution contours msg Press Enter to continue pause;cl con exac z 1 fi;0.01 msg Exact solution contours ENDUSE TEXT(USP 2D UNSTEADY DIFFUSION PROBLEM NX=10;NY=10;LSTEP=5 GROUP 2. Transience; time-step specification STEADY=F;GRDPWR(T,LSTEP,1.,1.0) GROUP 3. X-direction grid specification GRDPWR(X,NX,1,1.0) GROUP 4. Y-direction grid specification GRDPWR(Y,NY,1,1.0) GROUP 7. Variables stored, solved & named SOLVE(TEM1);STORE(EXAC) GROUP 8. Terms (in differential equations) & devices TERMS(TEM1,N,N,Y,P,P,P) GROUP 9. Properties of the medium (or media) PRNDTL(TEM1)=1.0;ENUL=1.0 GROUP 11. Initial values REAL(TCOR,XCOR,YCOR,DTC,DXC,DYC) DTC=TLAST/LSTEP DXC=XULAST/NX DYC=YVLAST/NY USP related parameters USP = T UAUTO = F USPDBG = F UTCPLT = T USPIMB = F MXLEV = 4 MYLEV = 4 MZLEV = 4 DOMAT = -1 MINPRP = -1 MAXPRP = 250 CELLST = 10 FACEST = 10 USPREL = 0.7 PARSOL = F ISG62 = 0 ISG60 = 1 Following commands set the initial field as.. TEM1 = X + Y DO II=1,NX XCOR=0.5*DXC+(II-1)*DXC DO JJ=1,NY + YCOR=0.5*DYC+(JJ-1)*DYC + PATCH(I:II:I:JJ:,INIVAL,:II:,:II:,:JJ:,:JJ:,1,NZ,1,1) + INIT(I:II:I:JJ:,TEM1,0.0,XCOR+YCOR) + INIT(I:II:I:JJ:,EXAC,0.0,XCOR+YCOR+TLAST) ENDDO ENDDO GROUP 13. Boundary conditions and special sources Following commands set the west values as.. TEM1 = T + Y DO II=1,LSTEP TCOR=II*DTC DO JJ=1,NY + YCOR=0.5*DYC+(JJ-1)*DYC + PATCH(W:II:W:JJ:,WWALL,1,1,:JJ:,:JJ:,1,NZ,:II:,:II:) + COVAL(W:II:W:JJ:,TEM1,1.,TCOR+YCOR) ENDDO ENDDO Following commands set the east values as.. TEM1 = T + 1 + Y DO II=1,LSTEP TCOR=II*DTC DO JJ=1,NY + YCOR=0.5*DYC+(JJ-1)*DYC + PATCH(E:II:E:JJ:,EWALL,NX,NX,:JJ:,:JJ:,1,NZ,:II:,:II:) + COVAL(E:II:E:JJ:,TEM1,1.,TCOR+1.0+YCOR) ENDDO ENDDO Following commands set south values as.. TEM1 = T + X DO II=1,LSTEP TCOR=II*DTC DO JJ=1,NX + XCOR=0.5*DXC+(JJ-1)*DXC + PATCH(S:II:S:JJ:,SWALL,:JJ:,:JJ:,1,1,1,NZ,:II:,:II:) + COVAL(S:II:S:JJ:,TEM1,1.,TCOR+XCOR) ENDDO ENDDO Following commands set north values as.. TEM1 = T + 1 + X DO II=1,LSTEP TCOR=II*DTC DO JJ=1,NX + XCOR=0.5*DXC+(JJ-1)*DXC + PATCH(N:II:N:JJ:,NWALL,:JJ:,:JJ:,NY,NY,1,NZ,:II:,:II:) + COVAL(N:II:N:JJ:,TEM1,1.,TCOR+1.+XCOR) ENDDO ENDDO Following commands set the volumetric source as.. 1 PATCH(SOURC,VOLUME,1,NX,1,NY,1,NZ,1,LSTEP) COVAL(SOURC,TEM1,FIXFLU,1.0) GROUP 15. Termination of sweeps LITER(TEM1)=20 ENDIT(TEM1)=1.e-5 RESFAC=1.E-7 LSWEEP=5 GROUP 21. Print-out of variables IXMON=NX/2;IYMON=NY/2 OUTPUT(TEM1,Y,Y,Y,Y,Y,Y) GROUP 24. Dumps for restarts dmpstk=t DISTIL=T EX(TEM1)=2.000E+00; EX(EXAC)=2.000E+00 IDISPA=1 CSG1=A STOP