Merge branch 'master' into update_meson_instructions

Author: bmunguia

_tutorials/design_features/Inc_Turbulent_Bend_Opt/Inc_Turbulent_Bend_Opt.md

@@ -135,7 +135,7 @@ As you can see, the row of cells just above the symmetry plane has collapsed ont
 ### constrained FFD deformation
 
 The problem here is that the mesh nodes on the symmetry plane are not allowed to move vertically, they only move horizontally outward inside the symmetry plane. Unfortunately, the FFD deformation is such that mesh nodes just above the symmetry plane are moved down, almost on the symmetry plane. To improve the quality of the mesh deformation, we disallow the vertical movement of the FFD box nodes on the nodes in the bottom plane of the FFD box, with j-index 0 and vertical displacement (0,1,0). In Figure (3), the plane with index j=0 is the bottom plane, indicated in yellow. So we remove entries in the **DV_PARAM** list of the form *(BOX, i_Ind, 0, k_Ind, 0,1,0)*. Additionally, we also disallow the vertical movement of the nodes in the plane j=1.
-Since we disallow vertical movement in 2x(6x6)=72 nodes in the planes with $$j=0$$ and $$j=1$$,  The total degrees of freedom is then $$648 - 72 = 576$$ d.o.f.
+Since we disallow vertical movement in 2x(6x6)=72 nodes in the planes with $$j=0$$ and $$j=1$$,  The total degrees of freedom is then $$648 - 72 = 576$$ d.o.f. 
 
 
 ![Pressure bend](../../../tutorials_files/design_features/Inc_Turbulent_Bend/opt_iter0_pressure_ffdbox.png "Pressure distribution")