Abstract: A gas flow device including a compact supersonic diffuser for converting high-velocity low-pressure gaseous flow to low-velocity high-pressure gaseous flow. The compact supersonic diffuser includes a plurality of wedges disposed in the diffuser duct that, by selectively initiating a series of interacting shocks on the gaseous flow, convert the flow to lower velocities and higher pressures in a shorter path.

Abstract: Disclosed is a low flow, low Reynolds number cavitating venturi. This cavitating venturi includes an inlet for receiving a liquid at an upstream pressure and an outlet for discharging the liquid received by the inlet at a downstream pressure. The liquid passes through a converging portion having a converging sidewall which extends from said inlet, through a throat portion having a throat sidewall and a diverging diffuser portion having a diverging sidewall. The cavitating venturi provides a substantially stable liquid flow rate independent of the downstream pressure up to a downstream pressure at least as high as 80% of the upstream pressure at a Reynolds number of 60,000 or less.

Abstract: A valve (10) for controlling flow of hydraulic fluid. The valve (10) has first and second valve members (80, 82) which have a plurality of lands and grooves. The valve members (80, 82) are relatively movable from a neutral position to a displaced position in which surface segments (202, 226, 208, 218) of respective pairs of lands overlap to form flow gaps (232, 234) for restricting flow of fluid between respective pairs of grooves. At least one (234) of the flow gaps is divergent by having a cross-sectional flow area which increases along a direction of fluid flow and at least one (232) of the flow gaps is convergent by having a cross-sectional flow area which decreases along a direction of fluid flow. The flow gaps (232, 234) have minimum cross-sectional flow areas (A, B) defined by the surface segments.

Abstract: A valve for controlling flow of hydraulic fluid. The valve includes a valve sleeve and a valve core. The core is disposed within the sleeve. The core and sleeve are relatively rotatable. Each of said core and sleeve has an axially extending land and an axially extending groove. The core and sleeve have relative rotational positions such that the lands overlap to define a flow gap for flow of hydraulic fluid from the groove in the sleeve to the groove in the core. The flow gap has a minimum cross-sectional flow area adjacent to the groove in the core. The minimum cross-sectional flow area constantly varies as the core and sleeve relatively rotate. The land on the sleeve has a notch immediately adjacent to, and downstream of the minimum cross-sectional flow area which provides an abrupt increase in cross-sectional flow area for suppressing valve noise due to cavitation.

Abstract: A valve for controlling flow of hydraulic fluid. The valve includes a valve sleeve and a valve core. The core is disposed within the sleeve. The core and sleeve are relatively rotatable. The sleeve has grooves connected to a utilization device. The core has grooves connected to a fluid supply and reservoir. The core and sleeve have lands which radially overlap during relative rotation of said core and sleeve to restrict fluid flow from a portion of the grooves in the sleeve to the grooves in the core connected to the reservoir. The lands on the sleeve have chamfered end faces with tapered segments.

Abstract: A wind tunnel in which high energy laser beam impingement studies can be ducted such that beam distortion and degradation is substantially precluded. Uniform, low turbulence flow in which thermal blooming, creation of wakes is substantially eliminated is attained by providing an improved elongated cylindrical settling chamber having a gradual turning radius. A transverse aerodynamic window is located in the low velocity flow turning region of the settling chamber which allows the entry of the laser beam and the exhaust of a turbulent sonic free-jet constituting 10 percent of the total fluid flow through the wind tunnel.

Abstract: A low pressure gas laser is provided with an aerodynamic window for the generated high power laser beam. The window comprises a duct with an oblique opening located in the supersonic part of and aligned with the axis of a Laval nozzle, having an atmospheric entrance. This permits extraction of the beam from the laser without any contact through a solid window.