The cut-off frequency of the anechoic chamber is 70 Hz. Wire mesh platforms can be mount ed on the floor above the wedges, or the floor wedges can be removed completely to make the chamber into a hemi-anechoic chamber. The Applied Research Laboratory has a 9,000 cu.ft. water tank, with mobile experimental platforms and mid-depth window portals, for use with laser based experiments and for viewing of submerged equipment. The tank is equipped with a measurement positioning system that is automated in two dimensions and can be manually positioned in the third. One wall of the rectangular test section is a mylar belt that is supported by large rollers at the up and downstream ends of the tunnel.
Air is supplied by a large centrifugal blower located in a sound isolation enclosure.
Hot-wire anemometry and microphone systems are available to measure the flow and acoustic parameters of interest. The flow field in the long rectangular duct is driven by an isolated centrifugal blower. A hot-wire anemometry system is available to measure the tu rbulence, and microphone systems are available to map acoustic fields in the duct along with wall pressure statistics. Typically, the test bodies are acoustic sensors such as pressure, or pressure gradient hydrophones which may be exposed to ocean currents in real applications. The ambient noise of this facility is equivalent to that sensed in the deep ocean under sea state 1 conditions.