Krapivsky, P. L.
We consider a particle diffusing inside a wedge with absorbing boundaries and driven by a radial flow of incompressible fluid generated by a source at the apex. The survival probability decays as (time)(-beta) with beta depending on the opening angle of the wedge and the Reynolds number associated with the hydrodynamic flow. The computation of the exponent beta reduces to finding the ground-state energy of the quantum particle in an infinitely deep potential well with a shape determined by the radial flow velocity.