This work compares the numerical results of a three-dimensional hydrodynami
c baroclinic model and a known analytical solution due to Baines of the bar
oclinic lunar semidiurnal (M2) tidal propagation over the continental shelf
. The simplifying numerical approaches are the Boussinesq and the hydrostat
ic hypothesis. The hydrostatic pressure restricts the use of this model to
every phenomenon associated with major vertical accelerations, as is someti
mes the case of internal tides near steep slopes. A comparison between the
two models in the area of the continental shelf was performed for 2.5, 5 an
d 10 per cent shelf slopes. The results obtained are the following: (a) the
linear numerical solution approaches the analytical solution for these slo
pes, (b) the convection terms become significant for slopes greater than 5
per cent and (c) the non-linear numerical model becomes unstable for slopes
above 10 per cent, therefore requiring non-hydrostatic pressure.