fix the bug of io.cpp caused by VOF implementation

src/rheology/incflo_rheology.cpp

@@ -89,7 +89,6 @@ void incflo::compute_viscosity_at_level (int /*lev*/,
               eta_arr(i,j,k) = m_mu*(1.-tracer_arr(i,j,k,0))+m_mu_s[0]*tracer_arr(i,j,k,0);
             });
         }
-
       }
     }
     else

src/utilities/io.cpp

@@ -597,6 +597,7 @@ void incflo::WritePlotVariables(Vector<std::string> vars, const std::string& plo
                                            &vel_eta,
                                            &m_leveldata[lev]->density,
                                            &m_leveldata[lev]->velocity,
+                                           &m_leveldata[lev]->tracer,
                                            Geom(lev),
                                            m_cur_time, 0);
             }