Introduce unstrained-flow for BurnerFlame

include/cantera/oneD/StFlow.h

@@ -171,21 +171,31 @@ class StFlow : public Domain1D
     virtual shared_ptr<SolutionArray> asArray(const double* soln) const;
     virtual void fromArray(SolutionArray& arr, double* soln);
 
-    //! Set flow configuration for freely-propagating flames, using an internal
-    //! point with a fixed temperature as the condition to determine the inlet
-    //! mass flux.
+    //! Set flow configuration for freely-propagating flames, using an internal point
+    //! with a fixed temperature as the condition to determine the inlet mass flux.
     void setFreeFlow() {
         m_type = cFreeFlow;
         m_dovisc = false;
         m_isFree = true;
+        m_usesLambda = false;
     }
 
-    //! Set flow configuration for axisymmetric counterflow or burner-stabilized
-    //! flames, using specified inlet mass fluxes.
+    //! Set flow configuration for axisymmetric counterflow flames, using specified
+    //! inlet mass fluxes.
     void setAxisymmetricFlow() {
         m_type = cAxisymmetricStagnationFlow;
         m_dovisc = true;
         m_isFree = false;
+        m_usesLambda = true;
+    }
+
+    //! Set flow configuration for burner-stabilized flames, using specified inlet mass
+    //! fluxes.
+    void setUnstrainedFlow() {
+        m_type = cAxisymmetricStagnationFlow;
+        m_dovisc = false;
+        m_isFree = false;
+        m_usesLambda = false;
     }
 
     //! Return the type of flow domain being represented, either "Free Flame" or
@@ -482,6 +492,7 @@ class StFlow : public Domain1D
 
     bool m_dovisc;
     bool m_isFree;
+    bool m_usesLambda;
 
     //! Update the transport properties at grid points in the range from `j0`
     //! to `j1`, based on solution `x`.

interfaces/cython/cantera/_onedim.pyx

@@ -733,6 +733,20 @@ cdef class FreeFlow(_FlowBase):
     _domain_type = "free-flow"
 
 
+cdef class UnstrainedFlow(_FlowBase):
+    r"""An unstrained flow domain. The equations solved are standard equations for
+    adiabatic one-dimensional flow. The solution variables are:
+
+    *velocity*
+        axial velocity
+    *T*
+        temperature
+    *Y_k*
+        species mass fractions
+    """
+    _domain_type = "unstrained-flow"
+
+
 cdef class AxisymmetricFlow(_FlowBase):
     r"""
     An axisymmetric flow domain. The equations solved are the similarity equations for
@@ -794,14 +808,15 @@ cdef class IdealGasFlow(_FlowBase):
 
     .. deprecated:: 3.0
 
-        Class to be removed after Cantera 3.0; replaced by `FreeFlow` and
-        s`AxisymmetricFlow`.
+        Class to be removed after Cantera 3.0; replaced by `FreeFlow`,
+        `AxisymmetricFlow` and `UnstrainedFlow`.
     """
     _domain_type = "gas-flow"
 
     def __init__(self, *args, **kwargs):
-        warnings.warn("Class to be removed after Cantera 3.0; use 'FreeFlow' "
-                      "or AxisymmetricFlow' instead.", DeprecationWarning)
+        warnings.warn("Class to be removed after Cantera 3.0; use 'FreeFlow', "
+                      "'AxisymmetricFlow' or 'UnstrainedFlow' instead.",
+                      DeprecationWarning)
         super().__init__(*args, **kwargs)
 
 

interfaces/cython/cantera/onedim.py

@@ -1067,7 +1067,7 @@ def __init__(self, gas, grid=None, width=None):
             Defines a grid on the interval [0, width] with internal points
             determined automatically by the solver.
 
-        A domain of class `AxisymmetricFlow` named ``flame`` will be created to
+        A domain of class `UnstrainedFlow` named ``flame`` will be created to
         represent the flame. The three domains comprising the stack are stored as
         ``self.burner``, ``self.flame``, and ``self.outlet``.
         """
@@ -1080,8 +1080,8 @@ def __init__(self, gas, grid=None, width=None):
 
         if not hasattr(self, 'flame'):
             # Create flame domain if not already instantiated by a child class
-            #: `AxisymmetricFlow` domain representing the flame
-            self.flame = AxisymmetricFlow(gas, name='flame')
+            #: `UnstrainedFlow` domain representing the flame
+            self.flame = UnstrainedFlow(gas, name='flame')
 
         if width is not None:
             grid = np.array([0.0, 0.1, 0.2, 0.3, 0.5, 0.7, 1.0]) * width

src/oneD/DomainFactory.cpp

@@ -53,6 +53,11 @@ DomainFactory::DomainFactory()
         ret->setAxisymmetricFlow();
         return ret;
     });
+    reg("unstrained-flow", [](shared_ptr<Solution> solution, const string& id) {
+        StFlow* ret = new StFlow(solution, id);
+        ret->setUnstrainedFlow();
+        return ret;
+    });
 }
 
 DomainFactory* DomainFactory::factory()

src/oneD/StFlow.cpp

@@ -132,7 +132,10 @@ string StFlow::type() const {
     if (m_isFree) {
         return "free-flow";
     }
-    return "axisymmetric-flow";
+    if (m_usesLambda) {
+        return "axisymmetric-flow";
+    }
+    return "unstrained-flow";
 }
 
 void StFlow::setThermo(IdealGasPhase& th) {
@@ -730,9 +733,9 @@ bool StFlow::componentActive(size_t n) const
 {
     switch (n) {
     case c_offset_V: // spread_rate
-        return !m_isFree;
+        return m_usesLambda;
     case c_offset_L: // lambda
-        return !m_isFree;
+        return m_usesLambda;
     case c_offset_E: // eField
         return false;
     default: