photon use
p
parphi

gr ou z 1
gr ou z m
gr y m
pause
gr off
red
gr ou x 1
gr ou z 1
do kk=1,20
con h1 z kk fi;0.01
enddo
gr ou z m
pause
con off
red
msg pressure contours on an axial plane; Press return for vectors
con p1 x 1 fi;0.01
gr ou z m
pause
msg velocity vectors on plane between fins.
msg Press e to end. Other wise enter command
con off
red
vec x m sh
gr ou z m
enduse

GROUP 1.  Run title and other preliminaries
TEXT(Internally-Finned Pipe; Laminar
TITLE
DISPLAY
The radial fins are continuous, thin, uniformly spaced.
Fluid enters the pipe with uniform velocity and temperature;
A constant temperature is prescribed for both fins and pipe wall.

x--->    Pipe wall (1/48 radian segment)
******    /
Fin |       ***                   Constant temperature
^       \ |           **                         |
|        \|            /         ^       .-.-----|-----.--
|         |                      |r    /     \           \
r         |         /            |   -|-->    |           |
-|-->    |           |
Symmetry |      /--Symmetry    Fixed  \     /           /
plane \            plane       mass,    `-'-----------'--
\ |   /                 momentum and  z---->
\                      enthalpy fluxes
|/
Note that the above sketch suggests the the fin projects only
part of the way towards the axis; but the patch representing
the fin wall in fact  extends to the axis.
This is altogther a poor representation of a finned tube,
no simulation is effected of the reduction in surface
temperature with diminishing radius resulting from the finite
conductivity of the fin material.
This library case should be replaced by one which is more
realistic.

The Q1 file contains PHOTON USE commands.

The locally-defined variables are as follows:

NFIN           number of fins
DPIP           pipe diameter
TWAL           wall temperature
TIN            inlet temperature
WIN            inlet velocity.
ENDDIS

REAL(WIN,DPIP,TWAL,TIN,REYNLDS);INTEGER(NFIN)
NFIN=24; WIN=0.1; DPIP=0.08; TWAL=25.0; TIN=20.0

GROUP 2. Transience; time-step specification
GROUP 3. X-direction grid specification
CARTES=F; IREGX=1; GRDPWR(X,10,3.1416/NFIN,1.2)

GROUP 4. Y-direction grid specification
IREGY=1; GRDPWR(Y,10,0.5*DPIP,-2.0)

GROUP 5. Z-direction grid specification
PARAB=T; IREGZ=1; GRDPWR(Z,20,0.1,1.0)

GROUP 6. Body-fitted coordinates or grid distortion
GROUP 7. Variables stored, solved & named
SOLVE(P1,W1,U1,V1,H1)

GROUP 8. Terms (in differential equations) & devices
TERMS(H1,N,P,P,P,P,P)

GROUP 9. Properties of the medium (or media)
PRNDTL(H1)=0.70;REYNLDS=WIN*YVLAST*2.0/ENUL
REYNLDS

GROUP 13. Boundary conditions and special sources

** Uniform velocity and temperature at the inlet
INLET(IN,LOW,#1,#NREGX,#1,#NREGY,#1,#1,1,1)
VALUE(IN,P1,1.0*WIN);VALUE(IN,W1,WIN);VALUE(IN,H1,TIN)

** Constant temperature at fin surface.
WALL (FINWALL,WEST,#1,#1,#1,#NREGY,#1,#NREGZ,1,1)
COVAL(FINWALL,W1,1.0,0.0);COVAL(FINWALL,V1,1.0,0.0)
COVAL(FINWALL,H1,1.0,TWAL)

** Constant temperature at pipe wall.
WALL (PIPEWALL,NORTH,#1,#NREGX,#NREGY,#NREGY,#1,#NREGZ,1,1)
COVAL(PIPEWALL,W1,1.0,0.0);COVAL(PIPEWALL,U1,1.0,0.0)
COVAL(PIPEWALL,H1,1.0,TWAL)

GROUP 14. Downstream pressure for PARAB=.TRUE.
GROUP 15. Termination of sweeps
LITHYD=10;SELREF=T;RESFAC=0.01

GROUP 16. Termination of iterations
LITER(U1)=10;LITER(V1)=10;LITER(W1)=10
GROUP 17. Under-relaxation devices
RELAX(U1,FALSDT,1.0);RELAX(V1,FALSDT,1.0);RELAX(W1,FALSDT,1.0)

GROUP 22. Spot-value print-out
TSTSWP=LITHYD;IPLTL=LITHYD;IYMON=NY/2+1;IXMON=NX/2;UWATCH=T

GROUP 23. Field print-out and plot control
IXPRL=NX-1; NXPRIN=2; NYPRIN=2; NZPRIN=5
PATCH(EXIT,CONTUR,1,NX,1,NY,NZ,NZ,1,1);COVAL(EXIT,H1,0.0,10.0)
IDISPA=1;IDISPB=1;IDISPC=NZ