Recirculation zones are of practical importance in natural streams. They create slack flows where silting can occur. Their boundary replaces the actual geometry of the channel and modifies the discharge distribution in the cross-sections. It is thus important to know the size and length of the recirculation zones. Studies reported in the literature show that the behaviour of a recirculation downstream an expansion is affected by the so-called confinement effect which compares vertical and transverse scales of the open channel flows. Literature showed that it can be accounted for by a dimensionless bed friction number, defining two asymptotic regimes: "shallow" or "frictional" and "deep" or "non-frictional". The present work studies experimentally the recirculation length for other experimental conditions, and notably with aspect ratios of the expansion different from 2. The results confirm the influence of the bed friction number but show that other flow parameters can be of primary importance. The Froude number appears to have no action, at least when the flow remains subcritical. Conversely, the aspect ratio of the expansion is shown to have a noticeable influence on the recirculation.