SOME POSSIBILITIES FOR SECURING A SMOOTH WATER SURFACE IN THE SNORT WATER TROUGH, AND AM APPRAISAL OF THE WATER-SURFACE SMOOTHING DEVICES

摘要

The Supersonic Naval Ordnance Research Track (SNORT) at HOTS has a water trough (which supplies water for use by the water brakes used to stop high-speed rocket teat sleds) whose bottom surface is inclined with respect to the horizontal. This means that a level water surface cannot be maintained in the trough and that running water, recalculated by pumps, must be used to obtain a desired water-surface profile. However, ripples and wavelets always exist over a running water surface and these may produce excessive fluctuations in the braking forces generated by various types of water brakes. Clearly, then, some methods must be found for smoothing such a water surface. Several means for accomplishing this result are investigated in this report. Among these an analysis is pre-sented for determining the effectiveness of a new water-surface smoothing device, which may have a wider applicability than that which is envisioned in this report. Essentially, the device con¬sists of a planning surface (like water skis), mounted to the sled by means of a pin joint and a suitably chosen set of springs and dash pots, which baa the property that the water surface behind it is "smoother" than that ahead of it. Hence, when such a device is mounted ahead of the water brake entrance sections, there will be a large decrease in the braking-force fluctuations.