Using the streamfunction solution, Torza derived analytical expressions for the velocity fields that could be used to derive analytical expressions for hydrodynamic stress on the interface for incompressible Newtonian fluids.
A possible solution to the problem was shown by Woldemar Voigt (1887), who investigated the Doppler effect for waves propagating in an incompressible elastic medium and deduced transformation relations that left the Wave equation in free space unchanged, and explained the negative result of the Michelson-Morley Experiment.
The BB condition has guided mathematicians and engineers to develop state-of-the-art formulations for many technologically important problems like Darcy flow, Stokes flow, incompressible Navier-Stokes, nearly incompressible elasticity.
Majda, Andrew J., Andrea L. Bertozzi, "Vorticity and Incompressible Flow".