Wind Tunnel Evaluation Research Articles

Behavior and survival of western spruce budworm,Choristoneura occidentalis Freeman, exposed to an ω-fluorinated pheromone analogue

ω-Fluorinated (E)-11-tetradecenal (14F-E11-14: Al) was synthesized using 1,10-decanediol as a starting compound. Male and female western spruce budworm,Choristoneura occidentalis Freeman, moths exposed to 14F-E11-14: Al had LC50s (CI) of 12.0 (7.4-19.5) µg and 41.7 (22.7-76.2) µg, respectively. Antennectomized moths had lower mortality rates than normal moths. 14F-E11-14:Al elicited slightly lower amplitudes than 97:3 (E/Z)-11-tetradecenal (E/Z11-14:Al) in electroantennogram studies, but the lag or recovery period following excitation by 14F-E11-14:Al was much lower than forE/Z11-14:Al at the same concentrations. 14F-E11-14:Al andE11-14:Al evoked similar responses from male moths in wind-tunnel evaluations but neither compound was as effective as a virgin female in stimulating moths to fly upwind to contact the lure.

Further development of pneumatic thrust-deflecting powered-lift systems

Wind-tunnel evaluations of two pneumatic thrust-deflecting powered-lift systems have been conducted to develop the capabilities of interchangeab le thrust recovery and reversal as well as longitudinal pitch trim. A circulation control wing/vectored thrust configuration employed underwing Pegasus-type nozzles to redirect the horizontal thrust component as needed for STOL operation and to provide nose-up pitching moment for trim. Although they provided a vertical thrust component to lift, the vectoring nozzles were relatively ineffective in augmenting aerodynamic lift. A circulation control wing/over the wing blowing configuration pneumatically deflected engine thrust for additional high lift beyond that provided by CCW alone. It also allowed pneumatic conversion of the resultant force along the flight path from thrust recovery to thrust reversal as required for takeoff or approach. Both configurations thus offer possible solutions to STOL operational problems, one by pneumatic/mechanical means and the other primarily pneumatically.

Diffusion in the vicinity of standard-design nuclear power plants--I. Wind-tunnel evaluation of diffusive characteristics of a simulated suburban neutral atmospheric boundary layer.

A large meteorological wind tunnel was used to simulate a suburban atmospheric boundary layer. The model-prototype scale was 1:300 and the roughness length was approximately 1.0 m full scale. The model boundary layer simulated full scale dispersion from ground-level and elevated release points over surfaces of comparable roughness length. This information should prove useful in a variety of transport and diffusion studies over short to moderate downwind distances. It will be used in Part II as the baseline data set with which to compare diffusion downwind of standard-design nuclear power plants.

Wind tunnel evaluation of the British Smoke Shade Sampler

The funnel-shaped inlet of the British Smoke Shade Sampler was tested in a wind tunnel to characterize aerosol penetration as a function of particle size and wind speed. Cutpoint sizes of 13.S and 10.8μm were noted at wind speeds of 2 and 8 km h −1, respectively. Tests of aerosol penetration through the complete sampling system, including the inlet, connecting tubing, manifold and filter holder, showed the cutpoint to be 4.4 μm. Tubing losses appear to control the transport of the larger particles.

Effect of Winglets on Performance and Handling Qualities of General Aviation Aircraft

Recent flight and wind tunnel evaluations of winglets mounted on general aviation airplanes have shown improvements in cruise fuel efficiency, and climbing and turning performance. Some of these analyses have also uncovered various effects of winglets on airplane handling qualities. Retrofitting an airplane with winglets can result in reduced cross wind take-off and landing capabilities. Also, winglets can have a detrimental effect on the lateral directional response characteristics of aircraft which have a moderate to high level of adverse yaw due to aileron. Introduction of an aileron-rudder-interconnect, and reduction of the effective dihedral by canting-in of the winglets, or addition of a lower winglet can eliminate these flying quality problems.

Wind tunnel evaluation of a modified andersen impactor and an all weather sampler inlet

Modifications were made to a one-cfm (4.72 × 10 −4 m 3/ s) Andersen impactor to permit the collection of larger particles than previously possible. An All Weather Sampler Inlet was developed for the unit which enables acquisition of unbiased aerosol samples for varying meteorological parameters. When tested with a uranine-tagged oleic acid aerosol in a wind tunnel operated at a speed of 4.6 m/s (15 ft/sec), the standard Andersen design precludes collection of more than 50 percent of particles larger than approximately 7 μm diameter whereas the corresponding particle size for the modified system is 14 μm. Wind tunnel tests with the modified unit show the performance to be relatively unaffected by wind speeds over the range of 5–15 ft/sec or by turbulence with intensities up to eight percent. The geometrical configuration precludes wind directional effects.

Evaluation of a simple open circuit wind tunnel for large droplet support

A simple open circuit vertical wind tunnel was constructed to provide an airflow that satisfied the several criteria necessary for the support of large water droplets (4–6 mm in diameter). Turbulence levels throughout the tunnel were measured, the effects of the various components on the airflow thus being shown. Much of the irregularity of flow in the working section was caused by the velocity profile shaping device immediately upstream. Measurements were made of the positional stability of droplets supported in the working section.

Wind tunnel evaluation of adhesive-coated cylinders as collection media in particulate sampling.

Abstract The collection efficiencies of an adhesive-coated cylindrical sampler were determined under controlled conditions with the aid of a specially constructed laboratory wind tunnel in which wind speeds could be varied between 5 mph and 40 mph. For size distributions having mean diameters of 31 to 36 microns, collection efficiencies were 24% at 5 mph, 37% at 10 mph, and 54% at 15 mph. Particle deposition was greatest in the leading 45° sector, dropping off sharply downwind of that region.