Abstract
We consider a viscous incompressible fluid flow governed by the Stokes system. We assume that a finite number of small inhomogeneities (particles) are immersed in the fluid. The reciprocity gap functional is introduced to describe the boundary data. An asymptotic formula for the reciprocity gap functional is derived. The obtained formulas can form the basis for very effective computational identification algorithms, aimed at determining information about inhomogeneities from boundary measurements.