  With the planning of new ambitious gravitational wave (GW) observatories,
fully controlled laboratory experiments on dynamic gravitation become more and
more important. Such new experiments can provide new insights in potential
dynamic effects such as gravitational shielding or energy flow and might
contribute to bringing light into the mystery still surrounding gravity. Here
we present a laboratory-based transmitter-detector experiment using two
rotating bars as transmitter and a 42 Hz, high-Q bending beam resonator as
detector. Using a highly precise phase control to synchronize the rotating
bars, a dynamic gravitational field emerges that excites the bending motion
with amplitudes up to 100 nm/s or 370 pm, which is a factor of 500 above the
thermal noise. The two-transmitter design enables the investigation of
different setup configurations. The detector movement is measured optically,
using three commercial interferometers. Acoustical, mechanical, and electrical
isolation, a temperature-stable environment, and lock-in detection are central
elements of the setup. The moving load response of the detector is numerically
calculated based on Newton's law of gravitation via discrete volume
integration, showing excellent agreement between measurement and theory both in
amplitude and phase. The near field gravitational energy transfer is 10$^{25}$
times higher than what is expected from GW analysis.
