READQ1_BEGIN DISPLAY The problem is similar to library case 110; but the heat loss is proportional to the fourth power of the temperature. This is effected by the "STAR-NAME" kind of PATCH in Group 13. READQ1_END ENDDIS GROUP 1. Run title and other preliminaries TEXT(Transient Radiation From Fin TITLE REAL(COEF,COND1,SPHT1); COND1=400.0; COEF=1.0E1; SPHT1=500.0 GROUP 2. Transience; time-step specification ** The transient lasts for 20 seconds STEADY=F; GRDPWR(T,10,20.0,1.0) GROUP 3. X-direction grid specification ** The fin length is 0.1 meters; grid is non-uniform GRDPWR(X,20,0.1,2.0) GROUP 4. Y-direction grid specification ** The fin thickness is twice YVLAST YVLAST=0.001 GROUP 7. Variables stored, solved & named SOLVE(TEMP) GROUP 8. Terms (in differential equations) & devices ** Built-in source and convection terms are cut out TERMS(TEMP,N,N,Y,Y,P,P) GROUP 9. Properties of the medium (or media) ENUL=1.0; RHO1=1.E4; PRNDTL(TEMP)=SPHT1*ENUL*RHO1/COND1 GROUP 11. Initialization of variable or porosity fields FIINIT(TEMP)=1.0 GROUP 13. Boundary conditions and special sources ** Heat loss per unit area = coef * temp * temp**3.0 PATCH(*TEMP,FREEN,1,NX,1,1,1,1,1,LSTEP) COVAL(*TEMP,TEMP,COEF,3.0) ** Fixed temperature at the fin root WALL (ROOT,WEST,1,1,1,1,1,1,1,LSTEP) COVAL(ROOT,TEMP,1.0/PRNDTL(TEMP),FIINIT(TEMP)) GROUP 15. Termination of sweeps ** The non-linear heat-loss term entails necessitates use of more than one sweep at each time step. LSWEEP=10 GROUP 17. Under-relaxation devices ** Under-relaxation is needed to procure convergence RELAX(TEMP,LINRLX,0.5) GROUP 19. Data communicated by satellite to GROUND ** GREX3 is used solely to print out the message at the top of the file, above "end". READQ1 effects this. READQ1=T;USEGRD=F SPEDAT(SET,GXMONI,TRANSIENT,L,F) GROUP 21. Print-out of variables OUTPUT(TEMP,Y,Y,Y,Y,Y,Y) GROUP 22. Spot-value print-out ITABL=1; TSTSWP=5;UWATCH=T GROUP 23. Field print-out and plot control NXPRIN=NX/10; NTPRIN=LSTEP/2; ORSIZ=0.4 PATCH(FIXEDTIM,PROFIL,1,NX,1,1,1,1,1,LSTEP) PLOT(FIXEDTIM,TEMP,0.0,1.0) PATCH(FINTIP,PROFIL,NX,NX,1,1,1,1,1,LSTEP) PLOT(FINTIP,TEMP,0.0,1.0) GROUP 24. Dumps for restarts