fix the subchandra second pert (#2553)

it was overriding the original pert, not adding to it

Exec/science/subchandra/problem_initialize_state_data.H

@@ -72,7 +72,7 @@ void problem_initialize_state_data (int i, int j, int k,
 
  // add a perturbation at the north pole
 
- Real t0 = state(i,j,k,UTEMP);
+ Real T0 = state(i,j,k,UTEMP);
 
  // perturbation is on the vertical-axis
 
@@ -92,8 +92,10 @@ void problem_initialize_state_data (int i, int j, int k,
  // convolve the temperature perturbation with the amount of He
  Real X_he = burn_state.xn[problem::ihe4];
 
- state(i,j,k,UTEMP) = t0 * (1.0_rt + X_he * problem::pert_temp_factor *
- (0.150e0_rt * (1.0_rt + std::tanh(2.0_rt - r1))));
+ Real Tpert = T0 * (1.0_rt + X_he * problem::pert_temp_factor *
+ (0.150e0_rt * (1.0_rt + std::tanh(2.0_rt - r1))));
+
+ Real dT = Tpert - T0;
 
 
 #if AMREX_SPACEDIM == 3
@@ -120,14 +122,17 @@ void problem_initialize_state_data (int i, int j, int k,
 
  // we are assuming here that the 2 perturbations don't overlap
 
- state(i,j,k,UTEMP) = t0 * (1.0_rt + X_he * problem::second_pert_temp_factor *
- (0.150e0_rt * (1.0_rt + std::tanh(2.0_rt - r2))));
+ Tpert = T0 * (1.0_rt + X_he * problem::second_pert_temp_factor *
+ (0.150e0_rt * (1.0_rt + std::tanh(2.0_rt - r2))));
+
+ dT += (Tpert - T0);
 
  }
 #endif
 
  burn_state.rho = state(i,j,k,URHO);
- burn_state.T = state(i,j,k,UTEMP);
+ burn_state.T = T0 + dT;
+
  // we don't need to refill xn, since it still holds unchanged from above
 
  eos(eos_input_rt, burn_state);