[cig-commits] commit 2055 by bangerth to /var/svn/dealii/aspect

[dealii.demon at gmail.com]

Revision 2055

Provide alternative descriptions of the thermal expansion coefficient
and the compressibility.

U   trunk/aspect/include/aspect/material_model/interface.h


http://www.dealii.org/websvn/revision.php?repname=Aspect+Repository&path=%2F&rev=2055&peg=2055

Diff:
Modified: trunk/aspect/include/aspect/material_model/interface.h
===================================================================
--- trunk/aspect/include/aspect/material_model/interface.h	2013-11-25 17:55:08 UTC (rev 2054)
+++ trunk/aspect/include/aspect/material_model/interface.h	2013-11-26 13:23:40 UTC (rev 2055)
@@ -333,7 +333,7 @@
                             const NonlinearDependence::Dependence dependence) const;
 
         /**
-        * Return the partial derivative of the compressibility function on the
+	 * Return the partial derivative of the compressibility function on the
         * variable indicates as last argument.
         *
         * The default implementation of this function returns zero
@@ -657,6 +657,10 @@
          * Return the compressibility coefficient
          * $rac 1
ho rac{\partial
ho}{\partial p}$ of the model as a
          * function of temperature, pressure and position.
+	 *
+	 * The compressibility can equivalently be computed as
+	 * $-rac 1V rac{\partial V}{\partial p}$. Note the difference
+	 * in sign.
          */
         virtual double compressibility (const double temperature,
                                         const double pressure,
@@ -679,6 +683,10 @@
         * $lpha=-rac{1}{
ho} rac{d
ho}{dT}$. Since the density
         * <i>decreases</i> with temperature for almost all models,
         * $lpha$ is usually positive.
+	*
+	* The thermal expansion coefficient can equivalently be computed as
+	* $rac 1V rac{\partial V}{\partial T}$. Note the difference
+	* in sign.
         *
         * This function has a default implementation that computes $lpha$
         * through its definition above, using the density() and density_derivative()