Simple (?) test problem does not work.

[artem_vb]

Hello, everybody

I'm trying to model the flows in the medium-size bay (50x70 km) with relatively complicated geometry. The grid is 100x100 points. Right now I'm trying to setup test problem with zero initial conditions and zero forces. The results supposed to be zero flow field etc., right? However I got the "BLOWUP" error. That's what I've done:

1) I used gridpack to generate curvilinear grid.
2) I used RPLUME test case. I edited the river inflow in 'analytical.f' to set to zero (temporarily).

After few 2D steps I've got overflowed Ocean%ubar and Ocean%ubar arrays (vertically integrated U-, V-momentum components). What am I doing wrong? What is the possible source of non-zero disturbances in otherwise completely "flat" problem?

Here is the list of C-preprocessing options:

Activated C-preprocessing Options:

ANA_BSFLUX Analytical kinematic bottom salinity flux.
ANA_BTFLUX Analytical kinematic bottom temperature flux.
ANA_INITIAL Analytical initial conditions.
ANA_PSOURCE Analytical point sources and sinks.
ANA_SMFLUX Analytical kinematic surface momentum flux.
ANA_SRFLUX Analytical kinematic shortwave radiation flux.
ANA_SSFLUX Analytical kinematic surface salinity flux.
ANA_STFLUX Analytical kinematic surface temperature flux.
ASSUMED_SHAPE Using assumed-shape arrays.
AVERAGES Writing out time-averaged fields.
AVERAGES_AKS Writing out time-averaged vertical S-diffusion.
AVERAGES_AKT Writing out time-averaged vertical T-diffusion.
AVERAGES_AKV Writing out time-averaged vertical viscosity.
CURVGRID Orthogonal curvilinear grid.
DEBUGGING Internal debugging switch activated.
DJ_GRADPS Parabolic Splines density Jacobian (Shchepetkin, 2002).
DOUBLE_PRECISION Double precision arithmetic.
EASTERN_WALL Wall boundary at Eastern edge.
LMD_BKPP KPP bottom boundary layer mixing.
LMD_CONVEC LMD convective mixing due to shear instability.
LMD_MIXING Large/McWilliams/Doney interior mixing.
LMD_NONLOCAL LMD convective nonlocal transport.
LMD_RIMIX LMD diffusivity due to shear instability.
LMD_SKPP KPP surface boundary layer mixing.
MASKING Land/Sea masking.
MIX_GEO_TS Mixing of tracers along geopotential surfaces.
NONLIN_EOS Non-linear Equation of State for seawater.
NORTHERN_WALL Wall boundary at Northern edge.
POWER_LAW Power-law shape time-averaging barotropic filter.
PROFILE Time profiling activated .
RIVERPLUME River Plume Example.
!RST_SINGLE Double precision fields in restart NetCDF file.
SALINITY Using salinity.
SOLVE3D Solving 3D Primitive Equations.
SPLINES Conservative parabolic spline reconstruction.
TS_A4HADVECTION Fouth-order Akima horizontal advection of tracers.
TS_A4VADVECTION Fouth-order Akima vertical advection of tracers.
TS_DIF2 Harmonic mixing of tracers.
TS_PSOURCE Tracers point sources and sinks.
UV_ADV Advection of momentum.
UV_COR Coriolis term.
UV_U3HADVECTION Third-order upstream bias advection of momentum.
UV_PSOURCE Mass point sources and sinks.
VAR_RHO_2D Variable density barotropic mode.
WESTERN_WALL Wall boundary at Western edge.

[marcelcure]

There are a few places in the code where divisions take place and where the possibility exists that the divisor equals 0 (especially if you are starting with some initail data fields that are set to zero). Some places where this occurs are u2dbc_im.F, v2dbc_im.F, zetabc.F and rho_eos.F. When I had this problem, I made sure that zero numbers where substituted by eps which was set to 1e-16 and that stopped the blowups.


Marcel Cure