diff --git a/include/cantera/oneD/StFlow.h b/include/cantera/oneD/StFlow.h
index 8cb26fbe0..069baf4ff 100644
--- a/include/cantera/oneD/StFlow.h
+++ b/include/cantera/oneD/StFlow.h
@@ -292,8 +292,19 @@ public:
         return m_rho[j];
     }
 
+    //! @deprecated To be removed after %Cantera 3.0. Superseded by isFree()
     virtual bool fixed_mdot();
 
+    /**
+     * Retrieve flag indicating whether flow is freely propagating.
+     * The flow is unstrained and the axial mass flow rate is not specified.
+     * For free flame propagation, the axial velocity is determined by the solver.
+     * @since New in %Cantera 3.0
+     */
+    bool isFree() const {
+        return m_isFree;
+    }
+
     void setViscosityFlag(bool dovisc) {
         m_dovisc = dovisc;
     }
diff --git a/src/oneD/Boundary1D.cpp b/src/oneD/Boundary1D.cpp
index 731ceb37b..2aed4e699 100644
--- a/src/oneD/Boundary1D.cpp
+++ b/src/oneD/Boundary1D.cpp
@@ -193,15 +193,15 @@ void Inlet1D::eval(size_t jg, double* xg, double* rg,
             rb[c_offset_T] -= m_temp;
         }
 
-        if (m_flow->fixed_mdot()) {
-            // The flow domain sets this to -rho*u. Add mdot to specify the mass
-            // flow rate.
-            rb[c_offset_L] += m_mdot;
-        } else {
+        if (m_flow->isFree()) {
             // if the flow is a freely-propagating flame, mdot is not specified.
             // Set mdot equal to rho*u, and also set lambda to zero.
             m_mdot = m_flow->density(0) * xb[c_offset_U];
             rb[c_offset_L] = xb[c_offset_L];
+        } else {
+            // The flow domain sets this to -rho*u. Add mdot to specify the mass
+            // flow rate.
+            rb[c_offset_L] += m_mdot;
         }
 
         // add the convective term to the species residual equations
@@ -390,7 +390,7 @@ void Outlet1D::eval(size_t jg, double* xg, double* rg, integer* diagg,
         int* db = diag - nc;
 
         // zero Lambda
-        if (m_flow_left->fixed_mdot()) {
+        if (!m_flow_left->isFree()) {
             rb[c_offset_U] = xb[c_offset_L];
         }
 
@@ -493,9 +493,7 @@ void OutletRes1D::eval(size_t jg, double* xg, double* rg,
         double* rb = r - nc;
         int* db = diag - nc;
 
-        if (!m_flow_left->fixed_mdot()) {
-            ;
-        } else {
+        if (m_flow_left->isFree()) {
             rb[c_offset_U] = xb[c_offset_L]; // zero Lambda
         }
         if (m_flow_left->doEnergy(m_flow_left->nPoints()-1)) {
diff --git a/src/oneD/Sim1D.cpp b/src/oneD/Sim1D.cpp
index d87abc117..39782ae57 100644
--- a/src/oneD/Sim1D.cpp
+++ b/src/oneD/Sim1D.cpp
@@ -688,7 +688,7 @@ int Sim1D::setFixedTemperature(double t)
         StFlow* d_free = dynamic_cast<StFlow*>(&domain(n));
         size_t npnow = d.nPoints();
         size_t nstart = znew.size();
-        if (d_free && !d_free->fixed_mdot()) {
+        if (d_free && d_free->isFree()) {
             for (size_t m = 0; m < npnow - 1; m++) {
                 bool fixedpt = false;
                 double t1 = value(n, c_offset_T, m);
@@ -766,7 +766,7 @@ double Sim1D::fixedTemperature()
     double t_fixed = std::numeric_limits<double>::quiet_NaN();
     for (size_t n = 0; n < nDomains(); n++) {
         StFlow* d = dynamic_cast<StFlow*>(&domain(n));
-        if (d && !d->fixed_mdot() && d->m_tfixed > 0) {
+        if (d && d->isFree() && d->m_tfixed > 0) {
             t_fixed = d->m_tfixed;
             break;
         }
@@ -779,7 +779,7 @@ double Sim1D::fixedTemperatureLocation()
     double z_fixed = std::numeric_limits<double>::quiet_NaN();
     for (size_t n = 0; n < nDomains(); n++) {
         StFlow* d = dynamic_cast<StFlow*>(&domain(n));
-        if (d && !d->fixed_mdot() && d->m_tfixed > 0) {
+        if (d && d->isFree() && d->m_tfixed > 0) {
             z_fixed = d->m_zfixed;
             break;
         }
diff --git a/src/oneD/StFlow.cpp b/src/oneD/StFlow.cpp
index 7ee6d0411..34da843b0 100644
--- a/src/oneD/StFlow.cpp
+++ b/src/oneD/StFlow.cpp
@@ -298,6 +298,8 @@ void StFlow::setGasAtMidpoint(const double* x, size_t j)
 }
 
 bool StFlow::fixed_mdot() {
+    warn_deprecated("StFlow::fixed_mdot", "To be removed after"
+        " Cantera 3.0. Replaced by isFree().");
     return !m_isFree;
 }
 
diff --git a/src/oneD/refine.cpp b/src/oneD/refine.cpp
index c34cbcb76..9d1fe555c 100644
--- a/src/oneD/refine.cpp
+++ b/src/oneD/refine.cpp
@@ -181,7 +181,7 @@ int Refiner::analyze(size_t n, const double* z, const double* x)
         }
 
         // Keep the point where the temperature is fixed
-        if (fflame && !fflame->fixed_mdot() && z[j] == fflame->m_zfixed) {
+        if (fflame && fflame->isFree() && z[j] == fflame->m_zfixed) {
             m_keep[j] = 1;
         }
     }