Coriolis effect is a coordinate force proportional to ω× v, where ω is the angular velocity of Earth directed to Noth and v is the velocity of the object. For bathtub v would be downwards, that is in the direction of Earth radius. At the equator Coriolis force is along the equator and non-vanishing. On the other hand, the force causing rotation of water in the bathtub is of opposite sign below and above equator and therefore vanishes at equator. Therefore Coriolis force is excluded as an explanation.
My own view is that this is a hydrodynamical effect and new physics might be involved. Turbulence is involved and vortex is generated. The direction of the rotation of the vortex should be understood. The selection of a specific direction violates parity symmetry and this gives in the TGD framework strong guidelines.
- The vortex is in the direction of the Earth's gravitational force. In the TGD framework, gravitational interaction is mediated by monopole flux tubes in the direction of the gravitational field. Quantum gravitation is involved and it is quite possible that the gravitational magnetic body (MB) induces the effect since quite generally MB plays a control role, in particular in living matter.
- The induced Kähler field contributes to both electromagnetic and classical (weak) Z0 field: since the matter is em neutral but not Z0 neutral, it seems that Z0 field must be in question. Could the gravitational MB of Earth consist of Z0 monopole flux tubes?
If this is the case, a macroscopic quantum effect involving a very large value ℏgr=GMm/β0 of gravitational Planck constant of the pair formed by Earth mass and particle must be in question since ordinary Z0 has extremely short range. The gravitational Compton length Λgr = ℏgr/m= GM/β0= r_S/2β0 does not depend on particle mass and Z0 is about .5 cm, one half of the Schwartschild radius of the Earth, for the favored β0=v0/c=1.
- In the classical Z0 field, particles with Z0 charges rotate around the axis of the field and since magnetic flux is approximately dipole field, the flux lines are radial but are upwards/downwards above/below the equator. This would explain why the rotation directions of the vortex are opposite and Northern and Southern hemispheres. The presence of the classical Z0 field, which violates parity symmetry, would also conform with the parity breaking and would be essential for the understanding of the mystery of chiral selection in biomatter.