c
c
c =====================================================
subroutine flux2(ixy,maxm,meqn,maux,mwaves,mbc,mx,
& q1d,dtdx1d,aux1,aux2,aux3,method,mthlim,
& faddm,faddp,gaddm,gaddp,cfl1d,wave,s,
& amdq,apdq,cqxx,bmasdq,bpasdq,work,mwork,
& rpn2,rpt2)
c =====================================================
c
c Author: Randall J. LeVeque
c Modified for AMROC: Ralf Deiterding
c
c # Compute the modification to fluxes f and g that are generated by
c # all interfaces along a 1D slice of the 2D grid.
c # ixy = 1 if it is a slice in x
c # 2 if it is a slice in y
c # This value is passed into the Riemann solvers. The flux modifications
c # go into the arrays fadd and gadd. The notation is written assuming
c # we are solving along a 1D slice in the x-direction.
c
c # fadd(i,.) modifies F to the left of cell i
c # gadd(i,.,1) modifies G below cell i
c # gadd(i,.,2) modifies G above cell i
c
c # The method used is specified by method(2:3):
c
c method(2) = 1 if only first order increment waves are to be used.
c = 2 if second order correction terms are to be added, with
c a flux-limiter as specified by mthlim.
c = 3 ==> Slope-limiting of the conserved variables, with a
c slope-limiter as specified by mthlim(1).
c > 3 ==> User defined slope-limiter method.
c Slope-limiting is intended to be used with dimensional
c splitting, but schemes that return the fluctuations might
c also be used in combination with transverse wave
c propagation. Note, that the application of MUSCL before
c transverse propagation corresponds to method(3)=2
c although internally the algorithm of method(3)=1 is
c used.
c
c method(3) = -1 0 Gives dimensional splitting using Godunov
c splitting, i.e. formally first order accurate.
c = -2 Dimensional splitting using Godunov splitting with
c boundary update after each directional step.
c The necessary ghost cell synchronization is done by
c the surrounding AMROC framework.
c This selection ensures that the solution of the
c splitting method is independent of the number of
c computational nodes.
c = 0 Gives the Donor cell method. No transverse
c propagation of neither the increment wave
c nor the correction wave.
c = 1 if transverse propagation of increment waves
c (but not correction waves, if any) is to be applied.
c = 2 if transverse propagation of correction waves is also
c to be included.
c
c Note that if mcapa>0 then the capa array comes into the second
c order correction terms, and is already included in dtdx1d:
c If ixy = 1 then
c dtdx1d(i) = dt/dx if mcapa= 0
c = dt/(dx*aux(i,jcom,mcapa)) if mcapa = 1
c If ixy = 2 then
c dtdx1d(j) = dt/dy if mcapa = 0
c = dt/(dy*aux(icom,j,mcapa)) if mcapa = 1
c
c Notation:
c The jump in q (q1d(i,:)-q1d(i-1,:)) is split by rpn2 into
c amdq = the left-going flux difference A^- Delta q
c apdq = the right-going flux difference A^+ Delta q
c Each of these is split by rpt2 into
c bmasdq = the down-going transverse flux difference B^- A^* Delta q
c bpasdq = the up-going transverse flux difference B^+ A^* Delta q
c where A^* represents either A^- or A^+.
c
c
implicit double precision (a-h,o-z)
include "call.i"
c
dimension q1d(1-mbc:maxm+mbc, meqn)
dimension amdq(1-mbc:maxm+mbc, meqn)
dimension apdq(1-mbc:maxm+mbc, meqn)
dimension bmasdq(1-mbc:maxm+mbc, meqn)
dimension bpasdq(1-mbc:maxm+mbc, meqn)
dimension cqxx(1-mbc:maxm+mbc, meqn)
dimension faddm(1-mbc:maxm+mbc, meqn)
dimension faddp(1-mbc:maxm+mbc, meqn)
dimension gaddm(1-mbc:maxm+mbc, meqn, 2)
dimension gaddp(1-mbc:maxm+mbc, meqn, 2)
dimension dtdx1d(1-mbc:maxm+mbc)
dimension aux1(1-mbc:maxm+mbc, maux)
dimension aux2(1-mbc:maxm+mbc, maux)
dimension aux3(1-mbc:maxm+mbc, maux)
dimension s(1-mbc:maxm+mbc, mwaves)
dimension wave(1-mbc:maxm+mbc, meqn, mwaves)
dimension method(7),mthlim(mwaves)
dimension work(mwork)
external rpn2, rpt2
logical limit
common /rpnflx/ mrpnflx
c
i0ql = 1
i0qr = i0ql + (maxm+2*mbc)*meqn
i0fl = i0qr + (maxm+2*mbc)*meqn
i0fr = i0fl + (maxm+2*mbc)*meqn
iused = i0fr + (maxm+2*mbc)*meqn - 1
c
if (iused.gt.mwork) then
write(6,*) '*** not enough work space in flux2ex'
write(6,*) '*** iused = ', iused, ' mwork =',mwork
stop
endif
c
limit = .false.
do 5 mw=1,mwaves
if (mthlim(mw) .gt. 0) limit = .true.
5 continue
c
c # initialize flux increments:
c -----------------------------
c
do 30 jside=1,2
do 20 m=1,meqn
do 10 i = 1-mbc, mx+mbc
faddm(i,m) = 0.d0
faddp(i,m) = 0.d0
gaddm(i,m,jside) = 0.d0
gaddp(i,m,jside) = 0.d0
10 continue
20 continue
30 continue
c
c
c # solve Riemann problem at each interface and compute Godunov updates
c ---------------------------------------------------------------------
c
if (method(2).le.2) then
call rpn2(ixy,maxm,meqn,mwaves,mbc,mx,q1d,q1d,maux,
& aux2,aux2,wave,s,amdq,apdq)
c
else
call slope2(ixy,maxm,meqn,maux,mwaves,mbc,mx,q1d,aux2,dx,dt,
& method,mthlim,wave,s,amdq,apdq,dtdx1d,rpn2,
& work(i0ql),work(i0qr),work(i0fl),work(i0fr))
endif
c
c # Set fadd for the donor-cell upwind method (Godunov)
do 40 m=1,meqn
do 40 i=1,mx+1
faddp(i,m) = faddp(i,m) - apdq(i,m)
faddm(i,m) = faddm(i,m) + amdq(i,m)
40 continue
c
c # compute maximum wave speed for checking Courant number:
cfl1d = 0.d0
do 50 mw=1,mwaves
do 50 i=1,mx+1
cfl1d = dmax1(cfl1d, dtdx1d(i)*dabs(s(i,mw)))
50 continue
c
if (method(2).le.1.or.method(2).ge.3) go to 130
c
if (mrpnflx.ne.0) then
write(6,*) '*** Riemann solver returns fluxes.'
write(6,*) '*** Wave limiting not possible.'
write(6,*) '*** Set method(2)>=3 for slope limiting.'
stop
endif
c
c # modify F fluxes for second order q_{xx} correction terms:
c -----------------------------------------------------------
c
c # apply limiter to waves:
if (limit) call limiter(maxm,meqn,mwaves,mbc,mx,wave,s,mthlim)
c
do 120 i = 1, mx+1
c
c # For correction terms below, need average of dtdx in cell
c # i-1 and i. Compute these and overwrite dtdx1d:
c
dtdx1d(i-1) = 0.5d0 * (dtdx1d(i-1) + dtdx1d(i))
c
do 120 m=1,meqn
cqxx(i,m) = 0.d0
do 119 mw=1,mwaves
c
c # second order corrections:
cqxx(i,m) = cqxx(i,m) + dabs(s(i,mw))
& * (1.d0 - dabs(s(i,mw))*dtdx1d(i-1)) * wave(i,m,mw)
c
119 continue
faddm(i,m) = faddm(i,m) + 0.5d0 * cqxx(i,m)
faddp(i,m) = faddp(i,m) + 0.5d0 * cqxx(i,m)
120 continue
c
if (method(3).eq.2) then
c # incorporate cqxx into amdq and apdq so that it is split also.
do 150 m=1,meqn
do 150 i = 1, mx+1
amdq(i,m) = amdq(i,m) + cqxx(i,m)
apdq(i,m) = apdq(i,m) - cqxx(i,m)
150 continue
endif
c
130 continue
c
if (method(3).le.0) go to 999 !# no transverse propagation
c
if (mrpnflx.ne.0) then
write(6,*) '*** Riemann solver returns fluxes.'
write(6,*) '*** Transverse wave propagation not possible.'
write(6,*) '*** Set method(3)<0 for dimensional splitting.'
stop
endif
c
c # modify G fluxes for transverse propagation
c --------------------------------------------
c
c
c # split the left-going flux difference into down-going and up-going:
call rpt2(ixy,maxm,meqn,mwaves,mbc,mx,
& q1d,q1d,maux,aux1,aux2,aux3,
& 1,amdq,bmasdq,bpasdq)
c
c # modify flux below and above by B^- A^- Delta q and B^+ A^- Delta q:
do 160 m=1,meqn
do 160 i = 1, mx+1
gupdate = 0.5d0*dtdx1d(i-1) * bmasdq(i,m)
gaddm(i-1,m,1) = gaddm(i-1,m,1) - gupdate
gaddp(i-1,m,1) = gaddp(i-1,m,1) - gupdate
c
gupdate = 0.5d0*dtdx1d(i-1) * bpasdq(i,m)
gaddm(i-1,m,2) = gaddm(i-1,m,2) - gupdate
gaddp(i-1,m,2) = gaddp(i-1,m,2) - gupdate
160 continue
c
c # split the right-going flux difference into down-going and up-going:
call rpt2(ixy,maxm,meqn,mwaves,mbc,mx,
& q1d,q1d,maux,aux1,aux2,aux3,
& 2,apdq,bmasdq,bpasdq)
c
c # modify flux below and above by B^- A^+ Delta q and B^+ A^+ Delta q:
do 180 m=1,meqn
do 180 i = 1, mx+1
gupdate = 0.5d0*dtdx1d(i-1) * bmasdq(i,m)
gaddm(i,m,1) = gaddm(i,m,1) - gupdate
gaddp(i,m,1) = gaddp(i,m,1) - gupdate
c
gupdate = 0.5d0*dtdx1d(i-1) * bpasdq(i,m)
gaddm(i,m,2) = gaddm(i,m,2) - gupdate
gaddp(i,m,2) = gaddp(i,m,2) - gupdate
180 continue
c
999 continue
return
end
c
c
c ===================================================================
subroutine slope2(ixy,maxm,meqn,maux,mwaves,mbc,mx,
& q,aux,dx,dt,method,mthlim,
& wave,s,amdq,apdq,dtdx,rpn2,
& ql,qr,fl,fr)
c ===================================================================
c
c # Implements the standard MUSCL-Hancock method. MUSCL must
c # be used to obtain 2nd order accuracy with conventional
c # finite-volume schemes that return the numerical fluxes instead
c # of fluctuations. Schemes returning the fluctuations can use MUSCL
c # slope-limiting or wave-limiting. Slope-limiting is intended to
c # be used with dimensional splitting, but wave propagation schemes
c # also can apply it in combination with transverse wave propagation.
c
c # Author: Ralf Deiterding, ralf@amroc.net
c
implicit double precision (a-h,o-z)
include "call.i"
common /rpnflx/ mrpnflx
c
dimension q(1-mbc:maxm+mbc, meqn)
dimension ql(1-mbc:maxm+mbc, meqn)
dimension qr(1-mbc:maxm+mbc, meqn)
dimension aux(1-mbc:maxm+mbc, maux)
dimension fl(1-mbc:maxm+mbc, meqn)
dimension fr(1-mbc:maxm+mbc, meqn)
dimension wave(1-mbc:maxm+mbc, meqn, mwaves)
dimension s(1-mbc:maxm+mbc, mwaves)
dimension amdq(1-mbc:maxm+mbc, meqn)
dimension apdq(1-mbc:maxm+mbc, meqn)
dimension dtdx(1-mbc:maxm+mbc)
dimension method(7),mthlim(mwaves)
external rpn2
c
mlim = 0
do 90 mw=1,mwaves
if (mthlim(mw) .gt. 0) then
mlim = mthlim(mw)
goto 95
endif
90 continue
95 continue
c
do 100 m=1,meqn
ql(1-mbc,m) = q(1-mbc,m)
qr(1-mbc,m) = q(1-mbc,m)
ql(mx+mbc,m) = q(mx+mbc,m)
qr(mx+mbc,m) = q(mx+mbc,m)
100 continue
c
if (method(2).gt.3) then
call rec2(ixy,maxm,meqn,mwaves,mbc,mx,q,method,mthlim,ql,qr)
c
c # MUSCL reconstruction with slope-limiting for conserved
c # variables. Linear reconstruction: om=0.d0
c # Quadratic spatial reconstuction: om!=0.d0
c # 2nd order spatial reconstruction: om=1.d0/3.d0
c # Reconstructions with om!=0.d0 are not conservative!
c
else
om = 0.d0
do 110 i=2-mbc,mx+mbc-1
do 110 m=1,meqn
call reclim(q(i,m),q(i-1,m),q(i+1,m),
& mlim,om,ql(i,m),qr(i,m))
110 continue
endif
c
call flx2(ixy,maxm,meqn,mbc,mx,ql,maux,aux,fl)
call flx2(ixy,maxm,meqn,mbc,mx,qr,maux,aux,fr)
c
do 200 i=2-mbc,mx+mbc-1
do 200 m=1,meqn
ql(i,m) = ql(i,m) + 0.5d0*dtdx(i)*(fl(i,m)-fr(i,m))
qr(i,m) = qr(i,m) + 0.5d0*dtdx(i)*(fl(i,m)-fr(i,m))
200 continue
c
call rpn2(ixy,maxm,meqn,mwaves,mbc,mx,ql,qr,maux,
& aux,aux,wave,s,amdq,apdq)
c
c # Add differences of fluxes between original and reconstructed values
c # to fluctuations, if a wave propagation scheme is applied.
c
if (mrpnflx.eq.0) then
call flx2(ixy,maxm,meqn,mbc,mx,ql,maux,aux,fl)
call flx2(ixy,maxm,meqn,mbc,mx,qr,maux,aux,fr)
do 300 i=2-mbc,mx+mbc-1
do 300 m=1,meqn
amdq(i,m) = amdq(i,m) + fr(i-1,m)
apdq(i,m) = apdq(i,m) - fl(i ,m)
300 continue
call flx2(ixy,maxm,meqn,mbc,mx,q,maux,aux,fl)
do 310 i=2-mbc,mx+mbc-1
do 310 m=1,meqn
amdq(i,m) = amdq(i,m) - fl(i-1,m)
apdq(i,m) = apdq(i,m) + fl(i ,m)
310 continue
endif
c
return
end
c
c
c ===================================================================
subroutine saverec2(ixy,maxm,maxmx,maxmy,mvar,meqn,mbc,mx,my,
& q,qls,qrs,qbs,qts,ql,qr)
c ===================================================================
c
c # Store reconstructed values for later use.
c
implicit double precision (a-h,o-z)
include "call.i"
c
dimension q(mvar, 1-mbc:maxmx+mbc, 1-mbc:maxmy+mbc)
dimension qls(mvar, 1-mbc:maxmx+mbc, 1-mbc:maxmy+mbc)
dimension qrs(mvar, 1-mbc:maxmx+mbc, 1-mbc:maxmy+mbc)
dimension qbs(mvar, 1-mbc:maxmx+mbc, 1-mbc:maxmy+mbc)
dimension qts(mvar, 1-mbc:maxmx+mbc, 1-mbc:maxmy+mbc)
dimension ql(1-mbc:maxm+mbc, meqn)
dimension qr(1-mbc:maxm+mbc, meqn)
c
if (ixy.eq.1) then
do 10 i = 1-mbc, mx+mbc
do m=1,meqn
qls(m,i,jcom) = ql(i,m)
qrs(m,i,jcom) = qr(i,m)
enddo
do m=meqn+1,mvar
qls(m,i,jcom) = q(m,i,jcom)
qrs(m,i,jcom) = q(m,i,jcom)
enddo
10 continue
endif
c
if (ixy.eq.2) then
do 20 j = 1-mbc, my+mbc
do m=1,meqn
qbs(m,icom,j) = ql(j,m)
qts(m,icom,j) = qr(j,m)
enddo
do m=meqn+1,mvar
qbs(m,icom,j) = q(m,icom,j)
qts(m,icom,j) = q(m,icom,j)
enddo
20 continue
endif
c
return
end
c