  The trajectories of a single bubble rising in the vicinity of a vertical
solid wall are experimentally investigated. Distinct initial wall-bubble
distances are considered for three different bubble rising regimes, i.e.
rectilinear, planar zigzag, and spiral. The problem is defined by three control
parameters, namely the Galilei number, $Ga$, the Bond number, $Bo$, and the
initial dimensionless distance between the bubble centroid and the wall, $L$.
We focus on high-Bond numbers, varying $L$ from 1 to 4, and compare the results
with the corresponding unbounded case, $L \rightarrow \infty$. In all cases,
the bubble deviates from the expected unbounded trajectory and migrates away
from the wall as it rises due to the overpressure generated in the gap between
the bubble and the wall. This repulsion is more evident as the initial
wall-bubble distance decreases. Moreover, in the planar zigzagging regime, the
wall is found to impose a preferential zigzagging plane perpendicular to it
when $L$ is small enough. Only slight wall effects are observed in the velocity
or the oscillation amplitude and frequency. The wall migration effect is more
evident for the planar zigzagging case and less relevant for the rectilinear
one. Finally, the influence of the vertical position of the wall is also
investigated. When the wall is not present upon release, the bubbles have the
expected behavior for the unbounded case and experience the migration only
instants before reaching the wall edge. This repulsion is, in general, more
substantial than in the initially-present-wall case.
