  The forces on an object impacting the water are extreme in the early moments
of water entry and can cause structural damage to biological and man-made
bodies alike. These early-time forces arise primarily from added mass, peaking
when the submergence is much less than one body length. We experimentally
investigate a means of reducing impact forces on rigid spheres by making a jet
of water strike the quiescent water surface prior to the object impacting. The
water jet accelerates the pool liquid and forms a cavity into which a sphere
falls. Through on-board accelerometer measurements and high speed imaging, we
quantify the force reduction compared to the case of a sphere entering a
quiescent pool. Finally, we find the emergence of a critical jet volume
required to maximize force reduction; the critical volume is rationalized using
scaling arguments informed by near-surface particle image velocimetry (PIV)
data.
