  Exact solutions are reported for a stream of asymmetric bubbles steadily
moving in a Hele-Shaw channel. From the periodicity along the streamwise
direction, the flow region is reduced to a rectangular unit cell containing one
bubble, which is conformally mapped to an annulus in an auxiliary complex
plane. Analytic expressions for the bubble shape as well as for the velocity
field are obtained in terms of the generalized Schwarz-Christoffel formula for
doubly connected domains.
