diff --git a/docs/source/FluidEquations.rst b/docs/source/FluidEquations.rst
index 54faa623da8a69a2e9a85dca8ee43f82a9f7b405..892774f66fe4338768a3c19d8c4675231fea4dc6 100644
--- a/docs/source/FluidEquations.rst
+++ b/docs/source/FluidEquations.rst
@@ -3,12 +3,21 @@ Fluid Equations
 
 Below are the governing equations for the fluid:
 
-.. math:: \frac{\partial (\epsilon_g \rho_g)}{\partial t} + \nabla \cdot (\epsilon_g \rho_g U_g)  = 0
+Conservation of fluid mass:
+
+.. math:: \frac{\partial (\varepsilon_g \rho_g)}{\partial t} + \nabla \cdot (\varepsilon_g \rho_g U_g)  = 0
   :label: eqn::mass_cons
 
-.. math:: \frac{ \partial (\epsilon_g \rho_g U)}{\partial t} + \nabla \cdot (\epsilon_g \rho_g U_g U_g) + \epsilon_g \nabla p_g = \nabla \cdot \tau + {\bf g}
+Conservation of fluid momentum:
+
+.. math:: \frac{ \partial (\varepsilon_g \rho_g U)}{\partial t} + \nabla \cdot (\varepsilon_g \rho_g U_g U_g) + \varepsilon_g \nabla p_g = \nabla \cdot \tau + {\bf g} 
+           + \sum_{part} \beta (V_{part} - U_g)
   :label: eqn::mom_cons
 
-.. math:: \frac{\partial \epsilon_g}{\partial t} + \nabla \cdot (\epsilon_g  U_g)  = 0
-  :label: eqn::mass_eps
+Conservation of fluid volume:
+
+where $\sum_{part} \beta (V_{part} - U_g)$ is the drag term in which $V_{part}$ represents the particle velocity.
+
+.. math:: \frac{\partial \varepsilon_g}{\partial t} + \nabla \cdot (\varepsilon_g  U_g)  = 0
+  :label: eqn::mass_vareps