Add nested FGMRES inner BiCGSTAB test case

Author: eorbay-metu

TestCases/rans/naca0012/turb_NACA0012_sa_nested.cfg

@@ -58,7 +58,16 @@ LIMITER_ITER= 99999
 
 % ------------------------ LINEAR SOLVER DEFINITION ---------------------------%
 %
-LINEAR_SOLVER= FGMRESandBCGSTAB2
+LINEAR_SOLVER= FGMRES
+%
+% Use nested Krylov solver (YES, NO).
+% When YES: FGMRES uses an inner Krylov solver (e.g. BCGSTAB).
+LINEAR_SOLVER_NESTED= YES
+
+% Inner solver used only when LINEAR_SOLVER_NESTED = YES.
+% Options: BCGSTAB
+LINEAR_SOLVER_INNER= BCGSTAB
+
 LINEAR_SOLVER_PREC= LU_SGS
 LINEAR_SOLVER_ERROR= 1E-5
 LINEAR_SOLVER_ITER= 5