Abstract: A fluid friction controller that includes an outer member having a first friction control surface and an inner member having a second friction control surface. The control surfaces coact to define an elongated orifice that diverges from its entrance toward its exit. The length of the orifice is related to the angle of divergence so that the flow of a fluid passing therethrough remains attached to the control surfaces and the dynamic pressure in the flow does not exceed the static pressure at any point along the length of the orifice.

Abstract: A throttling valve that has an outer ring unit having a plurality of superimposed cylindrical shaped outer throttling rings that define a series of annular passages between the rings. An inner ring unit also having a plurality of superimposed cylindrical shaped inner throttling rings is adapted to movably support the inner rings within the annular passages to establish elongated flow orifices between the adjacent surfaces of the rings. The geometry of each orifice is arranged so that the fluid in transit remains attached to the control surfaces of each orifice and to insure that the static pressure along the length of the orifice remains above the dynamic pressure. The tip region of each orifice is provided with a diverging flow section to further insure quiet performance along the entire length of the orifice.

Abstract: A protective tent structure of light weight, portable construction is formed by joining a plurality of flexible support members at upper and lower terminal ends of each for pivotal movement about a linear axis through the commonly joined upper and lower ends. The tent is movable between fully erected and folded positions and, when in its folded position, the support members may be manually moved from a normal, unflexed position to a flexed position wherein the terminal ends of the support members are spaced more closely than when the members are in their unflexed positions. A separate member with hook-shaped end portions is provided for releasably retaining the support members in the flexed position while the tent is folded. In the unflexed position, the support members all include a linear base portion and an arcuate support portion, the latter being engaged with a flexible fabric covering which forms the protective portion of the tent when in the erected position.