Effective black holes from non-Riemannian vortex acoustics in ABC flows

It is shown that the existence of effective black holes in non-Riemannian vortex acoustics is not forbidden under certain constraints on acoustic torsion vector. In Arnold-BeltramiChildress (ABC) flows only the spatial part acoustic torsion vertical vanish, which allows us to consider constraints on acoustic torsion to obtain artificial non-Riemannian black hole solutions in ABC flows. An explicity acoustic black hole solution is given for irrotational ABC flows, This solution is similar to Visser acoustic metric for a vortex flow. Actually a particular form of this acoustic metric is given for ABC flows. Effective BHs with acoustic torsioned vortex flows in effective spacetime. The Ricci scalar computed is the same as that of a string singularity and the black-hole ergoregion coincides with the event horizon.PACS numbers: 02.40.Hw:differential geometries.