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[Examples] Update C++ flamespeed to use current best-practices

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Wider, uniform initial grid; initial profiles with zero-gradient section
on both ends of the domain; skip initial fixed-temperature solve.
This commit is contained in:
Ray Speth 2016-04-14 15:01:25 -04:00
parent c0c9a4ef31
commit b50ef03838
1 changed files with 13 additions and 39 deletions
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52
samples/cxx/flamespeed/flamespeed.cpp
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@ -68,16 +68,13 @@ int flamespeed(double phi)
FreeFlame flow(&gas);
// create an initial grid
int nz=5;
doublereal lz=0.02;
vector_fp z(nz+1);
int nz = 6;
doublereal lz=0.1;
vector_fp z(nz);
doublereal dz=lz/((doublereal)(nz-1));
for (int iz=0; iz<nz; iz++) {
z[iz]=((doublereal)iz)*dz;
}
//add one node onto end of domain to help with zero gradient at outlet
z[nz]=lz*1.05;
nz++;
flow.setupGrid(nz, &z[0]);
@ -112,36 +109,17 @@ int flamespeed(double phi)
//----------- Supply initial guess----------------------
vector_fp locs;
vector_fp locs{0.0, 0.3, 0.7, 1.0};
vector_fp value;
locs.resize(3);
value.resize(3);
// ramp values from inlet to adiabatic flame conditions
// over 70% of domain and then level off at equilibrium
double z1=0.7;
double uout;
uout=inlet.mdot()/rho_out;
uin=inlet.mdot()/rho_in;
locs[0]=0.0;
locs[1]=z1;
locs[2]=1.0;
value[0]=uin;
value[1]=uout;
value[2]=uout;
double uout=inlet.mdot()/rho_out;
value = {uin, uin, uout, uout};
flame.setInitialGuess("u",locs,value);
value[0]=temp;
value[1]=Tad;
value[2]=Tad;
value = {temp, temp, Tad, Tad};
flame.setInitialGuess("T",locs,value);
for (size_t i=0; i<nsp; i++) {
value[0]=yin[i];
value[1]=yout[i];
value[2]=yout[i];
value = {yin[i], yin[i], yout[i], yout[i]};
flame.setInitialGuess(gas.speciesName(i),locs,value);
}
@ -153,26 +131,22 @@ int flamespeed(double phi)
int flowdomain=1;
double ratio=10.0;
double slope=0.2;
double curve=0.02;
double slope=0.08;
double curve=0.1;
flame.setRefineCriteria(flowdomain,ratio,slope,curve);
int loglevel=1;
bool refine_grid = true;
// Solve freely propagating flame
// Linearly interpolate to find location where this temperature would
// exist. The temperature at this location will then be fixed for
// remainder of calculation.
flow.fixTemperature();
refine_grid=false;
flame.setFixedTemperature(900.0);
flame.solve(loglevel,refine_grid);
refine_grid = true;
flame.setFixedTemperature(0.5 * (temp + Tad));
flow.solveEnergyEqn();
bool refine_grid = true;
flame.solve(loglevel,refine_grid);
double flameSpeed_mix = flame.value(flowdomain,flow.componentIndex("u"),0);
cout << "Flame speed with mixture-averaged transport: " <<