  Jetting of collapsing bubbles is a key aspect in cavitation-driven
fluid-solid interactions as it shapes the bubble dynamics and additionally due
to its direct interaction with the wall. We study experimentally and
numerically the near-wall collapse and jetting of a single bubble seeded into
the stagnation flow of a wall jet, i.e. a jet that impinges perpendicular onto
a solid wall. High-speed imaging shows rich and rather distinct bubble dynamics
for different wall jet flow velocities and bubble-to-wall stand-off distances.
The simulations use a Volume-of-Fluid method and allow to numerically determine
the microscopic and transient pressures and shear stresses on the wall. It is
shown that a wall jet at moderate flow velocities of a few metres per second
already shapes the bubble ellipsoidally inducing a planar and convergent jet
flow. The distinct bubble dynamics allow to tailor the wall interaction. In
particular, the shear stresses can be increased by orders of magnitude without
increasing impact pressures the same way. Interestingly, at small seeding
stand-offs, the bubble during the final collapse stage can lift off the wall
and migrate against the flow direction of the wall jet such that the violent
collapse occurs away from the wall.
