Simple set-up to test flow-dependent horizontal viscosity implementation.

 Domain size is 50 x 26 x 40 grid-cells,
 with uniform resolution dx=dy= 1.km , dz = 5.m

 Zonally re-entrant, flat bottom channel (closed by Northern Wall @ j=26)

 input files are real*8 (see matlab script input/gendata.m )

 start from initial density field (given by initial Temp), no forcing

 Test Exp. |  Momentum   |  Viscosity  | useFullLeith | Biharmonic | side-drag   |
           | formulation | formulation |              | vs harmonic| (no_slip BC)|
----------------------------------------------------------------------------------
 standard  | Vector-Inv. |  Vort-Div   |  FullLeith   |   viscC4   |    No       |
(dir=input)|             |             |              |            |             |
----------------------------------------------------------------------------------
 .A4FlxF   |  Flux-Form  |  FLux-Form  |  FullLeith   |   viscC4   |    Yes      |
----------------------------------------------------------------------------------
 .AhFlxF   |  Flux-Form  |  Flux-Form  |    No        |   viscC2   |    No       |
----------------------------------------------------------------------------------
 .AhVrDv   | Vector-Inv. |  Vort-Div   |  FullLeith   |   viscC2   |    Yes      |
----------------------------------------------------------------------------------
 .AhStTn   | Vector-Inv. | Strain-Tens |  FullLeith   |   viscC2   |    Yes      |
----------------------------------------------------------------------------------

Notes:
1) Stain-Tension viscosity formulation is used when setting
     useStrainTensionVisc=.TRUE.,
   and currently only available with Vector-Invariant momentum.
   Default is .False., to use Vorticity & Divergence formulation
   (pkg/mom_vecinv) or Flux-Form formulation (pkg/mom_fluxform)
2) test .A4FlxF (input.A4FlxF) starts from a pickup-file,
   all other test exp. start from iter0=0
3) test with Biharmonic visc. are using:
    viscC4leith = viscC4leithD = 1.85,
    viscC4smag  = 1.,
    viscA4GridMax = 1.,
4) test with Harmonic visc. are using:
    viscC2leith = viscC2leithD=1.85,
    viscC2smag  = 1.,
    viscAhGridMax = 1.,

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