add reference solution

Author: coding4Acause

tests/cl_cd_pitch_plunge_k=1.2_n=101_ref.dat

@@ -0,0 +1,41 @@
+0	0.186685576	-0.196376005
+0.025	1.470380746	-0.551823736
+0.05	1.508947008	-0.540508305
+0.075	1.483113647	-0.494333961
+0.1	1.401397781	-0.421932212
+0.125	1.266175838	-0.331771041
+0.15	1.083424271	-0.234640217
+0.175	0.864080384	-0.142249578
+0.2	0.622017843	-0.065157413
+0.225	0.372951039	-0.011220901
+0.25	0.132404587	0.015639815
+0.275	-0.087662306	0.015734454
+0.3	-0.281287571	-0.007384842
+0.325	-0.448728188	-0.048587382
+0.35	-0.594774074	-0.102621598
+0.375	-0.726262934	-0.164868405
+0.4	-0.849602058	-0.231338223
+0.425	-0.968799558	-0.298156213
+0.45	-1.084223864	-0.360921671
+0.475	-1.19217332	-0.414336876
+0.5	-1.285265137	-0.452406948
+0.525	-1.353524125	-0.469289554
+0.55	-1.386000792	-0.460615707
+0.575	-1.372732325	-0.424904121
+0.6	-1.306796704	-0.364596667
+0.625	-1.186111884	-0.286288967
+0.65	-1.014557093	-0.199929902
+0.675	-0.80201985	-0.117079497
+0.7	-0.563153165	-0.048650561
+0.725	-0.314950943	-0.002784176
+0.75	-0.073633095	0.016490014
+0.775	0.148359615	0.009416373
+0.8	0.344379849	-0.02045203
+0.825	0.513969473	-0.067855289
+0.85	0.661566564	-0.12735373
+0.875	0.794064784	-0.194199932
+0.9	0.918039326	-0.264356142
+0.925	1.037566696	-0.333911506
+0.95	1.153194269	-0.398485723
+0.975	1.261343239	-0.452821683
+1	1.354695219	-0.49095914