c c c c
c
      program interpolate
      implicit none
c
c     Demonstation of 2 simple interpolation methods for
c     smoothly joining results from 2 disjoint regions
c
c     John Mahaffy 2/3/96
c
c    Open up two files in your current directory to receive results
c
      open(10,file='nuwlin')
      open(11,file='nuwcube')
c
c   First a linear weighted transition
c
      call nuwlin
c
c   Next a cubic weighted transition
c
      call nuwcube
c
c   If you are in Hammond Lab, change this subroutine to plot results
c
      call plotit
c
      stop
      end
c
      subroutine nuwlin
      implicit none
      real Nulam,Nuturb,Pr,Re,w,Nu
      real Re1,Re2,rwfac
c
c   Demonstration of linearly weighted transition region
c   Calculation of Nusselt Number  with weighted transition
c   in Re1
      parameter (Pr=1.0,Nulam=4.0,Re1=640,Re2=2000.,rwfac=1./(Re2-Re1))
c 
c
      Re=0.0
c
c    Evaluate the Nusselt number over the range 0.<=Re<=3000.
c
      do 100 while (Re.le.3000.)
        if(Re.lt.Re1) then
           Nu = Nulam
        else if (Re.gt.Re2)  then
           Nu=Nuturb(Re,Pr)
        else
           w = (Re - Re1)*rwfac
           Nu = (1.-w)*Nulam + w*Nuturb(Re,Pr)
        endif
        write(10,*)Re,Nu
        Re=Re+10.
  100 continue
      return
      end
      subroutine nuwcube
      implicit none
      real Nuturb,Nulam,Pr,Re,w,SRe,Re1,Re2, Nu
c
c   Demonstration of cubic weighting in transition zone
c   Calculation of Nusselt Number  with weighted transition
c   in Re1
c 
c 
c