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  • src/1d/equations/euler/rprhok/rp1eurhok.f

    c
    c =========================================================
          subroutine rp1eurhok(maxmx,meqn,mwaves,mbc,mx,ql,qr,maux,
         &     auxl,auxr,wave,s,amdq,apdq)
    c =========================================================
    c
    c     # solve Riemann problems for the thermally perfect 1D multi-component 
    c     # Euler equations using Roe's approximate Riemann solver.  
    c
    c     # On input, ql contains the state vector at the left edge of each cell
    c     #           qr contains the state vector at the right edge of each cell
    c     # On output, wave contains the waves, 
    c     #            s the speeds, 
    c     #            amdq the  left-going flux difference  A^- \Delta q
    c     #            apdq the right-going flux difference  A^+ \Delta q
    c
    c     # Note that the i'th Riemann problem has left state qr(i-1,:)
    c     #                                    and right state ql(i,:)
    c     # From the basic clawpack routine step1, rp is called with ql = qr = q.
    c
    c     # Copyright (C) 2002 Ralf Deiterding, Georg Bader
    c     # Brandenburgische Universitaet Cottbus
    c
          implicit double precision (a-h,o-z)
          dimension   ql(1-mbc:maxmx+mbc, meqn)
          dimension   qr(1-mbc:maxmx+mbc, meqn)
          dimension    s(1-mbc:maxmx+mbc, mwaves)
          dimension wave(1-mbc:maxmx+mbc, meqn, mwaves)
          dimension amdq(1-mbc:maxmx+mbc, meqn)
          dimension apdq(1-mbc:maxmx+mbc, meqn)
    c
    c     # local storage
    c     ---------------
          parameter (max2 = 10002)  !# assumes at most 10000 grid points with mbc=2
          dimension u(-1:max2),enth(-1:max2),a(-1:max2)
          dimension g1a2(-1:max2)
          logical efix, pfix
    c
    c     define local arrays
    c
          include "ck.i"
    c
          dimension delta(LeNsp+2)
          dimension rkl(LeNsp), rkr(LeNsp)
          dimension hkl(LeNsp), hkr(LeNsp)
          dimension Y(LeNsp,-1:max2), pk(LeNsp,-1:max2)
    c
          data efix /.true./    !# use entropy fix for transonic rarefactions
          data pfix /.true./    !# use Larrouturou's positivity fix for species
    c
    c     # Riemann solver returns fluxes
    c     ------------
          common /rpnflx/ mrpnflx
          mrpnflx = 0
    c
          mu = Nsp+1
          mE = Nsp+2
          mT = Nsp+3
    c
    c     # Compute Roe-averaged quantities:
    c
          do 20 i=2-mbc,mx+mbc
             rhol = 0.d0
             rhor = 0.d0
             do k = 1, Nsp
                rkl(k) = qr(i-1,k)
                rkr(k) = ql(i  ,k)
                rhol = rhol + rkl(k)
                rhor = rhor + rkr(k)
             enddo
             if( rhol.le.1.d-10 ) then
                write(6,*) 'negative total density, left', rhol
                stop
             endif
             if( rhor.le.1.d-10 ) then
                write(6,*) 'negative total density, right', rhor
                stop
             endif
    c
    c        # compute left/right rho/W and rho*Cp
    c     
             rhoWl = 0.d0
             rhoWr = 0.d0
             do k = 1, Nsp
                rhoWl = rhoWl + rkl(k)/Wk(k)
                rhoWr = rhoWr + rkr(k)/Wk(k)
             enddo
    c
    c        # left/right Temperatures already calculated
    c
             Tl = qr(i-1,mT)
             Tr = ql(i  ,mT)
             pl = rhoWl*RU*Tl 
             pr = rhoWr*RU*Tr
    c
    c        # compute quantities for rho-average
    c
             rhsqrtl = dsqrt(rhol)  
             rhsqrtr = dsqrt(rhor)
             rhsq2 = rhsqrtl + rhsqrtr
    c
    c        # find rho-averaged specific velocity and enthalpy
    c
             u(i) = (qr(i-1,mu)/rhsqrtl +
         &           ql(i  ,mu)/rhsqrtr) / rhsq2
             enth(i) = (((qr(i-1,mE)+pl)/rhsqrtl
         &             + (ql(i  ,mE)+pr)/rhsqrtr)) / rhsq2  
    c
    c        # compute rho-averages for T, cp, and W
    c
             T  = (Tl * rhsqrtl + Tr * rhsqrtr) / rhsq2
             W  = rhsq2 / (rhoWl/rhsqrtl + rhoWr/rhsqrtr) 
    c        
    c        # evaluate left/right entropies and mean cp
    c
             call tabintp( Tl, hkl, hms, Nsp )
             call tabintp( Tr, hkr, hms, Nsp )
             do k = 1, Nsp
                Y(k,i) = (rkl(k)/rhsqrtl + rkr(k)/rhsqrtr) / rhsq2
             enddo
             
             Cp = Cpmix( Tl, Tr, hkl, hkr, Y(1,i) )
             gamma1 = RU / ( W*Cp - RU )
             gamma  = gamma1 + 1.d0
    c
    c        # find rho-averaged specific enthalpies,
    c        # compute rho-averaged mass fractions and
    c        # compute partial pressure derivatives
    c
             tmp = gamma * RU * T / gamma1 
    *         ht = 0.d0
             do k = 1, Nsp
                hk     = (hkl(k)*rhsqrtl + hkr(k)*rhsqrtr) / rhsq2
    *            ht = ht + Y(k,i)*(hkl(k)*rhsqrtl + hkr(k)*rhsqrtr) / rhsq2
                pk(k,i) = 0.5d0*u(i)**2 - hk + tmp / Wk(k)
             enddo
    c
    *         write (6,4) qr(i-1,mE)+pl, ql(i,mE)+pr, 
    *     &        ht+0.5d0*u(i)**2, enth(i), ht+0.5d0*u(i)**2-enth(i) 
    * 4    format(e16.8,e16.8,e16.8,e16.8,e24.16)
    c
    c        # compute speed of sound
    c
             a2 = enth(i)-u(i)**2   
             do k = 1, Nsp
                a2 = a2 + Y(k,i) * pk(k,i)
             enddo
             g1a2(i) = 1.d0 / a2
             a(i) = dsqrt(gamma1*a2) 
    c
       20    continue
    c
    c
          do 30 i=2-mbc,mx+mbc
    c
    c        # find a1 thru a3, the coefficients of the mE eigenvectors:
    c
             dpdr = 0.d0
             dpY  = 0.d0
             drho = 0.d0
             do k = 1, Nsp
                delta(k) = ql(i,k) - qr(i-1,k)
                drho = drho + delta(k)
                dpdr = dpdr + pk(k,i) * delta(k)
                dpY  = dpY  + pk(k,i) * Y(k,i)
             enddo
             delta(mu) = ql(i,mu) - qr(i-1,mu)
             delta(mE) = ql(i,mE) - qr(i-1,mE)
    c
             a2 = g1a2(i)*(dpdr - u(i)*delta(mu) + delta(mE))
             a3 = 0.5d0*( a2 - ( u(i)*drho - delta(mu) )/a(i) )
             a1 = a2 - a3 
    c
    c
    c        # Compute the waves.
    c        # Note that the 1+k-waves, for 1 .le. k .le. Nsp travel at
    c        # the same speed and are lumped together in wave(.,.,2).
    c        # The 3-wave is then stored in wave(.,.,3).
    c
             do k = 1, Nsp
    c         # 1-wave
                wave(i,k,1) = a1*Y(k,i)
    c         # 2-wave
                wave(i,k,2) = delta(k) - Y(k,i)*a2
    c         # 3-wave
                wave(i,k,3) = a3*Y(k,i)
             enddo
    
    c      # 1-wave
             wave(i,mu,1) = a1*(u(i)-a(i))
             wave(i,mE,1) = a1*(enth(i) - u(i)*a(i))
             wave(i,mT,1) = 0.d0
             s(i,1) = u(i)-a(i)
    c
    c      # 2-wave
             wave(i,mu,2) = u(i)*(drho - a2)
             wave(i,mE,2) = u(i)**2*(drho - a2) - dpdr + dpY*a2
             wave(i,mT,2) = 0.d0
             s(i,2) = u(i)
    c
    c      # 3-wave
             wave(i,mu,3) = a3*(u(i)+a(i))
             wave(i,mE,3) = a3*(enth(i)+u(i)*a(i))
             wave(i,mT,3) = 0.d0
             s(i,3) = u(i)+a(i)
    c                  
       30 continue
    c
    c     # compute Godunov flux f0:
    c     --------------------------
    c
          if (efix) go to 110
    c
    c     # no entropy fix
    c     ----------------
    c
    c     # amdq = SUM s*wave   over left-going waves
    c     # apdq = SUM s*wave   over right-going waves
    c
          do 100 m=1,meqn
             do 100 i=2-mbc, mx+mbc
                amdq(i,m) = 0.d0
                apdq(i,m) = 0.d0
                do 90 mw=1,mwaves
                   if (s(i,mw) .lt. 0.d0) then
                      amdq(i,m) = amdq(i,m) + s(i,mw)*wave(i,m,mw)
                   else
                      apdq(i,m) = apdq(i,m) + s(i,mw)*wave(i,m,mw)
                   endif
     90         continue
      100 continue
          go to 900
      110 continue
    c
    c     # With entropy fix
    c     ------------------
    c
    c    # compute flux differences amdq and apdq.
    c    # First compute amdq as sum of s*wave for left going waves.
    c    # Incorporate entropy fix by adding a modified fraction of wave
    c    # if s should change sign.
    c
          do 200 i=2-mbc,mx+mbc
    c
    c        # check 1-wave:
    c        ---------------
    c
             rho  = 0.d0
             rhoW = 0.d0
             do k = 1, Nsp
                rkl(k) = qr(i-1,k)
                rho    = rho  + rkl(k)
                rhoW   = rhoW + rkl(k)/Wk(k)
             enddo
             rhou  = qr(i-1,mu)
             rhoE  = qr(i-1,mE)
             T     = qr(i-1,mT)
             rhoCp = avgtabip( T, rkl, cpk, Nsp )
             gamma = RU / ( rhoCp/rhoW - RU ) + 1.d0
             p = rhoW*RU*T
             c = dsqrt(gamma*p/rho)
             s0 = rhou/rho - c     !# u-c in left state (cell i-1)
    *        write(6,*) 'left state 0', a(i), c, T
    c 
    c        # check for fully supersonic case:
             if (s0.ge.0.d0 .and. s(i,1).gt.0.d0)  then
    c           # everything is right-going
                do 60 m=1,meqn
                   amdq(i,m) = 0.d0
       60       continue
                go to 200
             endif
    c
             rho   = 0.d0
             rhoW  = 0.d0
             do k = 1, Nsp
                rkl(k) = rkl(k) + wave(i,k,1)
                rho    = rho   + rkl(k)
                rhoW   = rhoW  + rkl(k)/Wk(k)
             enddo
             rhou = rhou + wave(i,mu,1)
             rhoE = rhoE + wave(i,mE,1)
             rhoe = rhoE - 0.5d0*rhou**2/rho
             if ( TabS.gt.T*TABFAC .or. T*TABFAC.gt.TabE ) then
                 write(6,*) 'Temperature out of range', T
                 write(6,*) 'state vector 1 before'
                 write(6,*) (rkl(k),k=1,Nsp)
             endif
             call SolveTrhok( T, rhoe, rhoW, rkl, Nsp, ifail)
             rhoCp = avgtabip( T, rkl, cpk, Nsp )
             if ( TabS.gt.T*TABFAC .or. T*TABFAC.gt.TabE ) then
                 write(6,*) 'Temperature out of range', T
                 write(6,*) 'state vector 1 after'
                 write(6,*) (rkl(k),k=1,Nsp)
             endif
             gamma = RU / ( rhoCp/rhoW - RU ) + 1.d0
             p = rhoW*RU*T
             c = dsqrt(gamma*p/rho)
             s1 = rhou/rho - c  !# u-c to right of 1-wave
    *        write(6,*) 'left state 1', a(i), c, T
    c
             if (s0.lt.0.d0 .and. s1.gt.0.d0) then
    c            # transonic rarefaction in the 1-wave
                 sfract = s0 * (s1-s(i,1)) / (s1-s0)
               else if (s(i,1) .lt. 0.d0) then
    c            # 1-wave is leftgoing
                 sfract = s(i,1)
               else
    c            # 1-wave is rightgoing
                 sfract = 0.d0   !# this shouldn't happen since s0 < 0
               endif
             do 120 m=1,meqn
                amdq(i,m) = sfract*wave(i,m,1)
      120    continue 
    c
    c        # check 2-wave:
    c        ---------------
    c
             if (s(i,2) .ge. 0.d0) go to 200  !# 2-wave is rightgoing
             do 140 m=1,meqn
                amdq(i,m) = amdq(i,m) + s(i,2)*wave(i,m,2)
      140    continue
    c
    c        # check 3-wave:
    c        ---------------
    c
             rho  = 0.d0
             rhoW = 0.d0
             do k = 1, Nsp
                rkr(k) = ql(i,k)
                rho    = rho   + rkr(k)
                rhoW   = rhoW  + rkr(k)/Wk(k)
             enddo
             rhou  = ql(i,mu)
             rhoE  = ql(i,mE)
             T     = ql(i,mT)
             rhoCp = avgtabip( T, rkr, cpk, Nsp )
             gamma = RU / ( rhoCp/rhoW - RU ) + 1.d0
             p = rhoW*RU*T
             c = dsqrt(gamma*p/rho)
             s3 = rhou/rho + c     !# u+c in right state  (cell i)
    *        write(6,*) 'right state 1', a(i), c, T
    c          
             rho  = 0.d0
             rhoW = 0.d0
             do k = 1, Nsp
                rkr(k) = rkr(k) - wave(i,k,3)
                rho    = rho   + rkr(k)
                rhoW   = rhoW  + rkr(k)/Wk(k)
             enddo
             rhou  = rhou - wave(i,mu,3)
             rhoE  = rhoE - wave(i,mE,3)
             rhoe  = rhoE - 0.5d0*rhou**2/rho
             if ( TabS.gt.T*TABFAC .or. T*TABFAC.gt.TabE ) then
                 write(6,*) 'Temperature out of range', T
                 write(6,*) 'state vector 1 before'
                 write(6,*) (rkr(k),k=1,Nsp)
             endif
             call SolveTrhok( T, rhoe, rhoW, rkr, Nsp, ifail)
             rhoCp = avgtabip( T, rkr, cpk, Nsp )
             if ( TabS.gt.T*TABFAC .or. T*TABFAC.gt.TabE ) then
                 write(6,*) 'Temperature out of range', T
                 write(6,*) 'state vector 1 after'
                 write(6,*) (rkr(k),k=1,Nsp)
             endif
             gamma = RU / ( rhoCp/rhoW - RU ) + 1.d0
             p = rhoW*RU*T
             c = dsqrt(gamma*p/rho)
             s2 = rhou/rho + c   !# u+c to left of 3-wave
    *        write(6,*) 'right state 0', a(i), c, T
    c
             if (s2 .lt. 0.d0 .and. s3.gt.0.d0) then
    c            # transonic rarefaction in the 3-wave
                 sfract = s2 * (s3-s(i,3)) / (s3-s2)
               else if (s(i,3) .lt. 0.d0) then
    c            # 3-wave is leftgoing
                 sfract = s(i,3)
               else
    c            # 3-wave is rightgoing
                 go to 200
               endif
    c
             do 160 m=1,meqn
                amdq(i,m) = amdq(i,m) + sfract*wave(i,m,3)
      160    continue
      200 continue
    c
    c     # compute the rightgoing flux differences:
    c     # df = SUM s*wave   is the total flux difference and apdq = df - amdq
    c
          do 220 m=1,meqn
             do 220 i = 2-mbc, mx+mbc
                df = 0.d0
                do 210 mw=1,mwaves
                   df = df + s(i,mw)*wave(i,m,mw)
      210       continue
                apdq(i,m) = df - amdq(i,m)
      220 continue 
    c
      900 continue
    c
          if (pfix) then
             do 70 i=2-mbc,mx+mbc
                amdr = 0.d0
                apdr = 0.d0
                rhol = 0.d0
                rhor = 0.d0
                do k = 1, Nsp
                   amdr = amdr + amdq(i,k)
                   apdr = apdr + apdq(i,k)
                   rhol = rhol + qr(i-1,k)
                   rhor = rhor + ql(i  ,k)
                enddo
                do 70 k=1,Nsp
                   if (qr(i-1,mu)+amdr.gt.0.d0) then
                      Z = qr(i-1,k)/rhol
                   else
                      Z = ql(i  ,k)/rhor
                   endif
                   amdq(i,k) = Z*amdr + (Z-qr(i-1,k)/rhol)*qr(i-1,mu)
                   apdq(i,k) = Z*apdr - (Z-ql(i  ,k)/rhor)*ql(i  ,mu)               
     70      continue  
          endif  
    c
          return
          end
    c
    c
    c  ***********************************************************
    c
          double precision function Cpmix( Tl, Tr, hl, hr, Y )
          implicit double precision(a-h,o-z)
          include  "ck.i"
    c
          dimension Y(*)
          dimension hl(*), hr(*)
          data Tol /1.d-6/
    c
          if( dabs(Tr-Tl).gt.Tol ) then
             Cp = 0.d0
             do k = 1, Nsp
                Cp = Cp + (hr(k)-hl(k)) * Y(k) 
             enddo
             Cp = Cp / (Tr-Tl)
          else
             T = 0.5d0*(Tr+Tl)
             Cp = avgtabip( T, Y, cpk, Nsp )
          endif
          Cpmix = Cp
    c
          return
          end
    
    

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