Remove up from fluid_2d_m residual. driven_cavity_2d_porous test case has slightly faster convergence, but still slow

Author: aabrown100-git

Code/Source/solver/fluid.cpp

@@ -1430,8 +1430,8 @@ void fluid_2d_m(ComMod& com_mod, const int vmsFlag, const int eNoNw, const int e
   // Residual contribution Birkman term 
   // Local residue
   for (int a = 0; a < eNoNw; a++) {
-      lR(0,a) = lR(0,a) + mu*K_inverse_darcy_permeability*w*Nw(a)*(u(0)+up(0));
-      lR(1,a) = lR(1,a) + mu*K_inverse_darcy_permeability*w*Nw(a)*(u(1)+up(1));
+      lR(0,a) = lR(0,a) + mu*K_inverse_darcy_permeability*w*Nw(a)*(u(0));
+      lR(1,a) = lR(1,a) + mu*K_inverse_darcy_permeability*w*Nw(a)*(u(1));
   }
 }