Affiliations: The First Research Center, Technical Research and
Development Institute, Japan Defense Agency, Naka-Meguro, Meguro, Tokyo,
153-8630, Japan. (Current affiliation: Dept. of Aeronautics and Astronautics,
School of Engineering, Tokai University, 1117, Kitakaname, Hiratsuka, Kanagawa,
259-1292 Japan) E-mail: mizukaki@keyaki.cc.u-tokai.ac.jp
Abstract: The flow visualization and force measurement of a supersonic
impinging jet on a center-holed vertical baffle plate were investigated.
Center-holed baffle plates of 2d to 5d in diameter, with a 1d center hole were
tested, where d is the bore of the launch tube. The standoff distance of the
baffle plates from the open end of the launch tube were varied to be from 2d to
5d. The supersonic impulse jet, with an incident shock wave of Mach 2.89 was
produced by a high-enthalpy blast-wave simulator. The direction-indicating
color schlieren method produced a two-dimensional density gradient of the flow
field around the baffle plate. In addition, the flow fields were numerically
analyzed, using two-dimensional asymmetric Euler equations. The results of the
numerically-analyzed and the experimentally-visualized flow field agreed well.
The visualized flow field indicates that the baffle plate should be at least
3.5d in diameter to deflect the supersonic impinging jet at an angle greater
than a right angle. We have concluded that the representative method of
designing muzzle brakes for military purpose accurately predicts the force
yielded by the supersonic impinging impulse jet on the vertical baffle plate
only when there is a large ratio of the baffle-plate diameter to the bore of
the launch tube.