Actual source code: ex33.c

petsc-master 2017-02-23
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  1: static char help[] = "Multiphase flow in a porous medium in 1d.\n\n";
  2:  #include <petscdm.h>
  3:  #include <petscdmda.h>
  4:  #include <petscsnes.h>

  6: typedef struct {
  7:   DM        cda;
  8:   Vec       uold;
  9:   Vec       Kappa;
 10:   PetscReal phi;
 11:   PetscReal kappaWet;
 12:   PetscReal kappaNoWet;
 13:   PetscReal dt;
 14:   /* Boundary conditions */
 15:   PetscReal sl, vl, pl;
 16: } AppCtx;

 18: typedef struct {
 19:   PetscScalar s; /* The saturation on each cell */
 20:   PetscScalar v; /* The velocity on each face */
 21:   PetscScalar p; /* The pressure on each cell */
 22: } Field;

 24: /*
 25:    FormPermeability - Forms permeability field.

 27:    Input Parameters:
 28:    user - user-defined application context

 30:    Output Parameter:
 31:    Kappa - vector
 32:  */
 33: PetscErrorCode FormPermeability(DM da, Vec Kappa, AppCtx *user)
 34: {
 35:   DM             cda;
 36:   Vec            c;
 37:   PetscScalar    *K;
 38:   PetscScalar    *coords;
 39:   PetscInt       xs, xm, i;

 43:   DMGetCoordinateDM(da, &cda);
 44:   DMGetCoordinates(da, &c);
 45:   DMDAGetCorners(da, &xs,NULL,NULL, &xm,NULL,NULL);
 46:   DMDAVecGetArray(da, Kappa, &K);
 47:   DMDAVecGetArray(cda, c, &coords);
 48:   for (i = xs; i < xs+xm; ++i) {
 49: #if 1
 50:     K[i] = 1.0;
 51: #else
 52:     /* Notch */
 53:     if (i == (xs+xm)/2) K[i] = 0.00000001;
 54:     else K[i] = 1.0;
 55: #endif
 56:   }
 57:   DMDAVecRestoreArray(da, Kappa, &K);
 58:   DMDAVecRestoreArray(cda, c, &coords);
 59:   return(0);
 60: }

 62: /*
 63:    FormFunctionLocal - Evaluates nonlinear residual, F(x) on local process patch
 64: */
 65: PetscErrorCode FormFunctionLocal(DMDALocalInfo *info, Field *u, Field *f, AppCtx *user)
 66: {
 67:   Vec            L;
 68:   PetscReal      phi        = user->phi;
 69:   PetscReal      dt         = user->dt;
 70:   PetscReal      dx         = 1.0/(PetscReal)(info->mx-1);
 71:   PetscReal      alpha      = 2.0;
 72:   PetscReal      beta       = 2.0;
 73:   PetscReal      kappaWet   = user->kappaWet;
 74:   PetscReal      kappaNoWet = user->kappaNoWet;
 75:   Field          *uold;
 76:   PetscScalar    *Kappa;
 77:   PetscInt       i;

 81:   DMGetGlobalVector(user->cda, &L);

 83:   DMDAVecGetArray(info->da, user->uold,  &uold);
 84:   DMDAVecGetArray(user->cda, user->Kappa, &Kappa);
 85:   /* Compute residual over the locally owned part of the grid */
 86:   for (i = info->xs; i < info->xs+info->xm; ++i) {
 87:     if (i == 0) {
 88:       f[i].s = u[i].s - user->sl;
 89:       f[i].v = u[i].v - user->vl;
 90:       f[i].p = u[i].p - user->pl;
 91:     } else {
 92:       PetscScalar K          = 2*dx/(dx/Kappa[i] + dx/Kappa[i-1]);
 93:       PetscReal   lambdaWet  = kappaWet*PetscPowScalar(u[i].s, alpha);
 94:       PetscReal   lambda     = lambdaWet + kappaNoWet*PetscPowScalar(1-u[i].s, beta);
 95:       PetscReal   lambdaWetL = kappaWet*PetscPowScalar(u[i-1].s, alpha);
 96:       PetscReal   lambdaL    = lambdaWetL + kappaNoWet*PetscPowScalar(1-u[i-1].s, beta);

 98:       f[i].s = phi*(u[i].s - uold[i].s) + (dt/dx)*((lambdaWet/lambda)*u[i].v - (lambdaWetL/lambdaL)*u[i-1].v);

100:       f[i].v = u[i].v + K*lambda*(u[i].p - u[i-1].p)/dx;

102:       /*pxx     = (2.0*u[i].p - u[i-1].p - u[i+1].p)/dx;*/
103:       f[i].p = u[i].v - u[i-1].v;
104:     }
105:   }
106:   DMDAVecRestoreArray(info->da, user->uold, &uold);
107:   DMDAVecRestoreArray(user->cda, user->Kappa, &Kappa);
108:   /* PetscLogFlops(11.0*info->ym*info->xm); */

110:   DMRestoreGlobalVector(user->cda, &L);
111:   return(0);
112: }

114: int main(int argc, char **argv)
115: {
116:   SNES           snes;   /* nonlinear solver */
117:   DM             da;     /* grid */
118:   Vec            u;      /* solution vector */
119:   AppCtx         user;   /* user-defined work context */
120:   PetscReal      t;      /* time */
122:   PetscInt       n;

124:   PetscInitialize(&argc, &argv, NULL,help);if (ierr) return ierr;
125:   /* Create solver */
126:   SNESCreate(PETSC_COMM_WORLD, &snes);
127:   /* Create mesh */
128:   DMDACreate1d(PETSC_COMM_WORLD,DM_BOUNDARY_NONE,4,3,1,NULL,&da);
129:   DMSetFromOptions(da);
130:   DMSetUp(da);
131:   DMSetApplicationContext(da, &user);
132:   SNESSetDM(snes, da);
133:   /* Create coefficient */
134:   DMDACreate1d(PETSC_COMM_WORLD,DM_BOUNDARY_NONE,4,1,1,NULL,&user.cda);
135:   DMSetFromOptions(user.cda);
136:   DMSetUp(user.cda);
137:   DMDASetUniformCoordinates(user.cda, 0.0, 1.0, 0.0, 1.0, 0.0, 1.0);
138:   DMGetGlobalVector(user.cda, &user.Kappa);
139:   FormPermeability(user.cda, user.Kappa, &user);
140:   /* Setup Problem */
141:   DMDASNESSetFunctionLocal(da,INSERT_VALUES,(PetscErrorCode (*)(DMDALocalInfo*,void*,void*,void*))FormFunctionLocal,&user);
142:   DMGetGlobalVector(da, &u);
143:   DMGetGlobalVector(da, &user.uold);

145:   user.sl  = 1.0;
146:   user.vl  = 0.1;
147:   user.pl  = 1.0;
148:   user.phi = 1.0;

150:   user.kappaWet   = 1.0;
151:   user.kappaNoWet = 0.3;

153:   /* Time Loop */
154:   user.dt = 0.1;
155:   for (n = 0; n < 100; ++n, t += user.dt) {
156:     PetscPrintf(PETSC_COMM_WORLD, "Starting time %g\n", t);
157:     VecView(u, PETSC_VIEWER_DRAW_WORLD);
158:     /* Solve */
159:     SNESSetFromOptions(snes);
160:     SNESSolve(snes, NULL, u);
161:     /* Update */
162:     VecCopy(u, user.uold);

164:     VecView(u, PETSC_VIEWER_DRAW_WORLD);
165:   }
166:   /* Cleanup */
167:   DMRestoreGlobalVector(da, &u);
168:   DMRestoreGlobalVector(da, &user.uold);
169:   DMRestoreGlobalVector(user.cda, &user.Kappa);
170:   DMDestroy(&user.cda);
171:   DMDestroy(&da);
172:   SNESDestroy(&snes);
173:   PetscFinalize();
174:   return ierr;
175: }