A study of fluid dynamics of gaseous nuclear rockets Quarterly progress report, 1 Jul. - 30 Sep. 1968

Predicting flow patterns of vortex tubes at high Reynolds number

Investigation of rotor blade tip-vortex aerodynamics

Several aspects of the aerodynamics of rotor blade tip vortices are examined. Two particular categories are dealt with; (1) dynamic loads on a blade passing close to or intersecting a trailing vortex, and (2) the response of the trailing vortex core to changes in the flow. Results for both categories are in reasonable agreement with existing data, although lower pressure gradients were obtained than anticipated for category one. A correlation between trailing edge sweep angle at the tip and vortex core size was noted for category two

A study of fluid dynamics of gaseous nuclear rockets Quarterly progress report, period ending Jun. 30, 1968

Bibliography on vortex flows for fluid dynamic containment of gaseous nuclear rocket fue

Estimates of the low-level wind shear and turbulence in the vicinity of Kennedy International Airport on 24 June 1975

A study was conducted to estimate the type of wind and turbulence distributions which may have existed at the time of the crash of Eastern Airlines Flight 66 while attempting to land. A number of different wind and turbulence profiles are predicted for the site and date of the crash. The morning and mid-afternoon predictions are in reasonably good agreement with magnitude and direction as reported by the weather observer. Although precise predictions cannot be made during the passage of the thunderstorm which coincides with the time of the accident, a number of different profiles which might exist under or in the vicinity of a thunderstorm are presented. The profile that is most probable predicts the mean headwind shear over 100 m (300 feet) altitude change and the average fluctuations about the mean headwind distribution. This combination of means and fluctuations leads to a reasonable probability that the instantaneous headwind shear would equal the maximum value reported in the flight recorder data

Total body calcium analysis using the Ca-12(n, alpha) Ar-37 reaction

A low dose neutron activation technique was developed to measure total body calcium in vivo. The effort had included development of irradiation and processing facilities and conduction of human studies to determine the accuracy and precision of measurement attainable with the systems

Total body calcium analysis

A technique to quantitate total body calcium in humans is developed. Total body neutron irradiation is utilized to produce argon 37. The radio argon, which diffuses into the blood stream and is excreted through the lungs, is recovered from the exhaled breath and counted inside a proportional detector. Emphasis is placed on: (1) measurement of the rate of excretion of radio argon following total body neutron irradiation; (2) the development of the radio argon collection, purification, and counting systems; and (3) development of a patient irradiation facility using a 14 MeV neutron generator. Results and applications are discussed in detail

Wind shear and turbulence around airports

A two part study was conducted to determine the feasibility of predicting the conditions under which wind/turbulence environments hazardous to aviation operations exist. The computer model used to solve the velocity temperature, and turbulence distributions in the atmospheric boundary layer is described, and the results of a parameteric analysis to determine the expected range of wind shear and turbulence to be encountered in the vicinity of airports are given. The second part describes the delineation of an ensemble of aircraft accidents in which low level wind shear and/or turbulence appeared to be causative factors. This set of accidents, encompassing a wide range of meteorological conditions, should prove useful in developing techniques for reconstructing hazardous wind environments for aircraft safety investigation purposes

Model predictions of wind and turbulence profiles associated with an ensemble of aircraft accidents

The feasibility of predicting conditions under which wind/turbulence environments hazardous to aviation operations exist is studied by examining a number of different accidents in detail. A model of turbulent flow in the atmospheric boundary layer is used to reconstruct wind and turbulence profiles which may have existed at low altitudes at the time of the accidents. The predictions are consistent with available flight recorder data, but neither the input boundary conditions nor the flight recorder observations are sufficiently precise for these studies to be interpreted as verification tests of the model predictions

Qualitative responses of a vortex core to tip blowing and intersecting airfoils

The qualitative responses of a trailing vortex core to change in its convective velocity produced by injection of air into the vortex core and by the flow field of a lifting surface in the path of the core are discussed. Flow pictures of the vortex core and vorticity measurements in the core show that an axial momentum injection of approximately 35% of the total wing drag alters the vortex structure and behavior quite drastically by effectively inducing a more rapid dispersion of the vorticity in the core. The data indicate that the phenomenon is governed by the rate of injection of the momentum rather than the mass flow rate. There also seems to be an optimum rate of injection beyond which increased injection does not bring about equally significant changes in the vortex core. Flow patterns of the region of interaction between the flow field of a lifting surface and the vortex core show two modes of vortex response; (1) the vortex core bends, following the streamline shape until it intercepts the wake of the wing where it is abruptly dispersed, or (2) the vortex core may be sliced into two similar vortices when the vortex hits the leading edge of the wing