  We investigate the influence of a shear flow on the process of nucleation.
Mesoscopic nonequilibrium thermodynamics is used to derive the Fokker-Planck
equation governing the evolution of the cluster size distribution in a
metastable phase subjected to a stationary flow. The presence of the flow
manifests itself in the expression for the effective diffusion coefficient of a
cluster and introduces modifications in the nucleation rate. The implications
of these results in condensation and polymer crystallization are discussed.
