Page 390 - Handbook Of Multiphase Flow Assurance

Computer code (Makogon, 1994, 1997) 389

C
Rsqred = Rhb(ndon)*Rhb(ndon)/Rsq
Ehb = Dhb(ndon)*Rsqred**5*(5.D0*Rsqred -6.D0)*Chbsq*Swtchr
nhbpoly=nhbpoly+1
ENDIF
ENDIF
10 Ener = Ener + Ecou + Elj + Ehb
end do
end do
Epoly(i,ii) = Ener
end do
end do
C
C
C Calculate interaction of polymer with the surface
Erun = 0.D0
C outer loop over all polymer segments
DO j=1,nbackbone
Esurf(j)=0.d0
do jj=1,monocount(j)
natom1 = monodata(j,jj)
nhbcount=0
Ener=0.D0
C ...inner loop over water molecules
DO 20 Iw = 1, Nwatrs
C ... loop over all atoms on each water molecule
DO 20 I = 1, 3
Ehb = 0.D0
Elj = 0.D0
Xi = xw(Iw,I)
Yi = yw(Iw,I)
Zi = zw(Iw,I)
Qi = qw(I)
C
Xij = Xi - xn(natom1)
Yij = Yi - yn(natom1)
Zij = Zi - zn(natom1)
C
C ... minimum image distances in x & y to keep surface under chain
if (ap.eq.1.or.ap.eq.3) then
C we are dealing with the [100] or [110] hydrate surface-rectangular box
IF (Yij .GT. ymaxh) Yij = Yij - ymax
IF (Yij .LT.-ymaxh) Yij = Yij + ymax
IF (Xij .GT. xmaxh) Xij = Xij - xmax