Address requested changes

Adjust tolerances, wrap long lines, and add document equations for isothermal compressibility and thermal expansion coefficient in PengRobinson and RedlichKwongMFTP
Cantera · Apr 26, 2023 · a9b5945 · a9b5945
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Showing 3 changed files with 32 additions and 10 deletions.
diff --git a/include/cantera/thermo/PengRobinson.h b/include/cantera/thermo/PengRobinson.h
@@ -205,10 +205,20 @@ class PengRobinson : public MixtureFugacityTP
 
 public:
 
-    //! Returns the isothermal compressibility. Units: 1/Pa.
+    //! Returns the isothermal compressibility (\f$\beta_T\f$). Units: 1/Pa.
+    /*!
+     *  \f[ 
+     *    \beta_T = \frac{1}{v} \left(\frac{\partial v}{\partial p}\right)_T
+     *  \f]
+     */
     virtual double isothermalCompressibility() const;
 
-    //! Return the volumetric thermal expansion coefficient. Units: 1/K.
+    //! Return the volumetric thermal expansion coefficient (\f$\alpha_V\f$). Units: 1/K.
+    /*!
+     *  \f[ 
+     *    \alpha_V = \frac{1}{v} \left(\frac{\partial v}{\partial T}\right)_p
+     *  \f]
+     */
     virtual double thermalExpansionCoeff() const;
 
     //! Calculate \f$dp/dV\f$ and \f$dp/dT\f$ at the current conditions

diff --git a/include/cantera/thermo/RedlichKwongMFTP.h b/include/cantera/thermo/RedlichKwongMFTP.h
@@ -173,10 +173,20 @@ class RedlichKwongMFTP : public MixtureFugacityTP
     virtual doublereal densSpinodalGas() const;
     virtual doublereal dpdVCalc(doublereal TKelvin, doublereal molarVol, doublereal& presCalc) const;
 
-    //! Returns the isothermal compressibility. Units: 1/Pa.
+    //! Returns the isothermal compressibility (\f$\beta_T\f$). Units: 1/Pa.
+    /*!
+     *  \f[ 
+     *    \beta_T = \frac{1}{v} \left(\frac{\partial v}{\partial p}\right)_T
+     *  \f]
+     */
     virtual double isothermalCompressibility() const;
 
-    //! Return the volumetric thermal expansion coefficient. Units: 1/K.
+    //! Return the volumetric thermal expansion coefficient (\f$\alpha_V\f$). Units: 1/K.
+    /*!
+     *  \f[ 
+     *    alpha_V = \frac{1}{v} \left(\frac{\partial v}{\partial T}\right)_p
+     *  \f]
+     */
     virtual double thermalExpansionCoeff() const;
 
     //! Calculate dpdV and dpdT at the current conditions

diff --git a/test/thermo/consistency.cpp b/test/thermo/consistency.cpp
@@ -74,8 +74,8 @@ class TestConsistency : public testing::TestWithParam<std::tuple<AnyMap, AnyMap>
         atol = setup.getDouble("atol", 1e-5);
         rtol_fd = setup.getDouble("rtol_fd", 1e-6);
         atol_v = setup.getDouble("atol_v", 1e-11);
-        atol_c = setup.getDouble("atol_c", 1e-8);
-        atol_e = setup.getDouble("atol_e", 1e-12);
+        atol_c = setup.getDouble("atol_c", 1e-14);
+        atol_e = setup.getDouble("atol_e", 1e-18);
 
         phase = cache[key];
         phase->setState(state);
@@ -362,7 +362,7 @@ TEST_P(TestConsistency, betaT_eq_minus_dmv_dP_const_T_div_mv)
     double P1 = phase->pressure();
     double mv1 = phase->molarVolume();
 
-    double P2 = P1 * (1 + 1e-7);
+    double P2 = P1 * (1 + 1e-6);
     phase->setState_TP(T, P2);
     double betaT2 = phase->isothermalCompressibility();
     double mv2 = phase->molarVolume();
@@ -371,7 +371,8 @@ TEST_P(TestConsistency, betaT_eq_minus_dmv_dP_const_T_div_mv)
     double mv_mid = 0.5 * (mv1 + mv2);
     double betaT_fd = -1 / mv_mid * (mv2 - mv1) / (P2 - P1);
 
-    EXPECT_NEAR(betaT_fd, betaT_mid, max({rtol_fd * betaT_mid, rtol_fd * betaT_fd, atol_c}));
+    EXPECT_NEAR(betaT_fd, betaT_mid, 
+                max({rtol_fd * betaT_mid, rtol_fd * betaT_fd, atol_c}));
 }
 
 TEST_P(TestConsistency, alphaV_eq_dmv_dT_const_P_div_mv)
@@ -387,7 +388,7 @@ TEST_P(TestConsistency, alphaV_eq_dmv_dT_const_P_div_mv)
     double T1 = phase->temperature();
     double mv1 = phase->molarVolume();
 
-    double T2 = T1 * (1 + 1e-7);
+    double T2 = T1 * (1 + 1e-6);
     phase->setState_TP(T2, P);
     double alphaV2 = phase->thermalExpansionCoeff();
     double mv2 = phase->molarVolume();
@@ -396,7 +397,8 @@ TEST_P(TestConsistency, alphaV_eq_dmv_dT_const_P_div_mv)
     double mv_mid = 0.5 * (mv1 + mv2);
     double alphaV_fd = 1 / mv_mid * (mv2 - mv1) / (T2 - T1);
 
-    EXPECT_NEAR(alphaV_fd, alphaV_mid, max({rtol_fd * alphaV_mid, rtol_fd * alphaV_fd, atol_e}));
+    EXPECT_NEAR(alphaV_fd, alphaV_mid, 
+                max({rtol_fd * alphaV_mid, rtol_fd * alphaV_fd, atol_e}));
 }
 
 // ---------- Tests for consistency of standard state properties ---------------