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rpn2ez_ptwise_geo.f.html |
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Source file: rpn2ez_ptwise_geo.f
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Directory: /home/rjl/git/rjleveque/clawpack-4.x/geoclaw/2d/lib
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Converted: Sun May 15 2011 at 19:15:41
using clawcode2html
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This documentation file will
not reflect any later changes in the source file.
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c
c
c =====================================================================
subroutine rpn2_ptwise(ixy, meqn, mwaves, ldw, maux,
& qLeft, qRight, auxLeft, auxRight,
& wave, s, amdq, apdq, rpfwave)
c =====================================================================
c
c Solves normal Riemann problems for the 2D SHALLOW WATER equations
c with topography:
c # h_t + (hu)_x + (hv)_y = 0 #
c # (hu)_t + (hu^2 + 0.5gh^2)_x + (huv)_y = -ghb_x #
c # (hv)_t + (huv)_x + (hv^2 + 0.5gh^2)_y = -ghb_y #
c
c # This is a new-style Riemann solver that works pointwise, with
c # Left state qLeft and right state qRight. (Note change in notation!!)
c
c
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
! !
! # This Riemann solver is for the shallow water equations. !
! !
! It allows the user to easily select a Riemann solver in !
! riemannsolvers_geo.f. this routine initializes all the variables !
! for the shallow water equations, accounting for wet dry boundary !
! dry cells, wave speeds etc. !
! !
! David George, Vancouver WA, Feb. 2009 !
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
use geoclaw_module
implicit none
integer meqn,mwaves,ixy,maux,ldw
double precision qLeft(meqn), qRight(meqn)
double precision auxLeft(maux), auxRight(maux)
double precision wave(ldw, mwaves)
double precision s(mwaves)
double precision amdq(meqn), apdq(meqn)
logical rpfwave
double precision drytol,g
!local only
integer m,i,mw,maxiter,mu,nv
double precision wall(3)
double precision fw(3,3)
double precision sw(3)
double precision hR,hL,huR,huL,uR,uL,hvR,hvL,vR,vL,phiR,phiL
double precision bR,bL,sL,sR,sRoe1,sRoe2,sE1,sE2,uhat,chat
double precision s1m,s2m
double precision hstar,hstartest,hstarHLL,sLtest,sRtest
double precision tw,dxdc
logical rare1,rare2
integer mcapa
common /cmcapa/ mcapa
g=grav
drytol=drytolerance
c
c # This solver returns fwaves:
rpfwave = .true.
!-----------------------Initializing-----------------------------------
!inform of a bad riemann problem from the start
if((qLeft(1).lt.0.d0).or.(qRight(1) .lt. 0.d0)) then
write(*,*) 'Negative input: hl,hr=',qLeft(1),qRight(1)
endif
!Initialize Riemann problem for grid interface
do mw=1,mwaves
s(mw)=0.d0
do m=1,meqn
wave(m,mw)=0.d0
enddo
enddo
c !set normal direction
if (ixy.eq.1) then
mu=2
nv=3
else
mu=3
nv=2
endif
!zero (small) negative values if they exist
if (qLeft(1).lt.0.d0) then
do m=1,meqn
qLeft(m)=0.d0
enddo
endif
if (qRight(1).lt.0.d0) then
do m=1,meqn
qRight(1)=0.d0
enddo
endif
!skip problem if in a completely dry area
if (qLeft(1).le.drytol.and.qRight(1).le.drytol) then
go to 30
endif
!Riemann problem variables
hL = qLeft(1)
hR = qRight(1)
huL = qLeft(mu)
huR = qRight(mu)
bL = auxLeft(1)
bR = auxRight(1)
hvL=qLeft(nv)
hvR=qRight(nv)
!check for wet/dry boundary
if (hR.gt.drytol) then
uR=huR/hR
vR=hvR/hR
phiR = 0.5d0*g*hR**2 + huR**2/hR
else
hR = 0.d0
huR = 0.d0
hvR = 0.d0
uR = 0.d0
vR = 0.d0
phiR = 0.d0
endif
if (hL.gt.drytol) then
uL=huL/hL
vL=hvL/hL
phiL = 0.5d0*g*hL**2 + huL**2/hL
else
hL=0.d0
huL=0.d0
hvL=0.d0
uL=0.d0
vL=0.d0
phiL = 0.d0
endif
wall(1) = 1.d0
wall(2) = 1.d0
wall(3) = 1.d0
if (hR.le.drytol) then
call riemanntype(hL,hL,uL,-uL,hstar,s1m,s2m,
& rare1,rare2,1,drytol,g)
hstartest=max(hL,hstar)
if (hstartest+bL.lt.bR) then !right state should become ghost values that mirror left for wall problem
c bR=hstartest+bL
wall(2)=0.d0
wall(3)=0.d0
hR=hL
huR=-huL
bR=bL
phiR=phiL
uR=-uL
vR=vL
elseif (hL+bL.lt.bR) then
bR=hL+bL
endif
elseif (hL.le.drytol) then ! right surface is lower than left topo
call riemanntype(hR,hR,-uR,uR,hstar,s1m,s2m,
& rare1,rare2,1,drytol,g)
hstartest=max(hR,hstar)
if (hstartest+bR.lt.bL) then !left state should become ghost values that mirror right
c bL=hstartest+bR
wall(1)=0.d0
wall(2)=0.d0
hL=hR
huL=-huR
bL=bR
phiL=phiR
uL=-uR
vL=vR
elseif (hR+bR.lt.bL) then
bL=hR+bR
endif
endif
!determine wave speeds
sL=uL-sqrt(g*hL) ! 1 wave speed of left state
sR=uR+sqrt(g*hR) ! 2 wave speed of right state
uhat=(sqrt(g*hL)*uL + sqrt(g*hR)*uR)/(sqrt(g*hR)+sqrt(g*hL)) ! Roe average
chat=sqrt(g*0.5d0*(hR+hL)) ! Roe average
sRoe1=uhat-chat ! Roe wave speed 1 wave
sRoe2=uhat+chat ! Roe wave speed 2 wave
sE1 = min(sL,sRoe1) ! Eindfeldt speed 1 wave
sE2 = max(sR,sRoe2) ! Eindfeldt speed 2 wave
!--------------------end initializing...finally----------
!solve Riemann problem.
maxiter = 1
call riemann_aug_JCP(maxiter,3,3,hL,hR,huL,
& huR,hvL,hvR,bL,bR,uL,uR,vL,vR,phiL,phiR,sE1,sE2,
& drytol,g,sw,fw)
c call riemann_ssqwave(maxiter,meqn,mwaves,hL,hR,huL,huR,
c & hvL,hvR,bL,bR,uL,uR,vL,vR,phiL,phiR,sE1,sE2,drytol,g,sw,fw)
c call riemann_wave(meqn,mwaves,hL,hR,huL,huR,hvL,hvR,
c & bL,bR,uL,uR,vL,vR,phiL,phiR,sE1,sE2,drytol,g,sw,fw)
c !eliminate ghost fluxes for wall
do mw=1,3
sw(mw)=sw(mw)*wall(mw)
do m=1,meqn
fw(m,mw)=fw(m,mw)*wall(mw)
enddo
enddo
do mw=1,mwaves
s(mw)=sw(mw)
wave(1,mw)=fw(1,mw)
wave(mu,mw)=fw(2,mw)
wave(nv,mw)=fw(3,mw)
enddo
30 continue
c==========Capacity for mapping from latitude longitude to physical space====
if (mcapa.gt.0) then
if (ixy.eq.1) then
dxdc=(Rearth*pi/180.d0)
else
dxdc=auxRight(3)
endif
do mw=1,mwaves
c if (s(mw) .gt. 316.d0) then
c # shouldn't happen unless h > 10 km!
c write(6,*) 'speed > 316: i,mw,s(mw): ',i,mw,s(mw)
c endif
s(mw)=dxdc*s(mw)
do m=1,meqn
wave(m,mw)=dxdc*wave(m,mw)
enddo
enddo
endif
c===============================================================================
c============= compute fluctuations=============================================
do m=1,meqn
amdq(m)=0.0d0
apdq(m)=0.0d0
do mw=1,mwaves
if (s(mw).lt.0.d0) then
amdq(m)=amdq(m) + wave(m,mw)
elseif (s(mw).gt.0.d0) then
apdq(m)=apdq(m) + wave(m,mw)
else
amdq(m) = amdq(m) + .5d0*wave(m,mw)
apdq(m) = apdq(m) + .5d0*wave(m,mw)
endif
enddo
enddo
return
end subroutine