A multidimensional finite element method for CFD

A finite element method is used to solve the equations of motion for 2- and 3-D fluid flow. The time-dependent equations are solved explicitly using quadrilateral (2-D) and hexahedral (3-D) elements, mass lumping, and reduced integration. A Petrov-Galerkin technique is applied to the advection terms. The method requires a minimum of computational storage, executes quickly, and is scalable for execution on computer systems ranging from PCs to supercomputers

Development of the ARIES parachute system

The design and testing of a two-stage parachute system to recover a space telescope weighing up to 2000 pounds is described. The system consists of a 15-ft dia ribbon parachute reefed to 50% for 10 seconds and a 73-ft dia paraform or cross second stage reefed to 10% for 10 seconds. The results of eight drop tests and one operational rocket launched flight and recovery are presented. A successful operational recovery of a 1600-lb NASA space telescope was conducted. The payload was launched by a second stage Minuteman rocket to an altitude of about 300 miles above sea level

Turbulent structure in the wake of sphere

The study of turbulent wakes is considered necessary to understand the droplet behavior associated with the collision coalescence phenomena in atmospheric clouds. The Vertical Atmospheric Wind Tunnel enables experiments dealing with this droplet behavior to be analyzed. The experiments conducted in the UMR Vertical Atmospheric Wind Tunnel consist of two parts: one is the investigation of the flow field characteristics in the test section of the wind tunnel; the other is the measurement of the turbulent structure in the wake of a sphere. The test section is rectangular in design and has a cross-sectional area of 36 square inches (6 inches X 6 inches). Mean velocity profiles show the flow to be uniform but increasing in magnitude throughout the downstream portion of the test section. Boundary layer thickness becomes noticeable during the latter portion of the test section. Turbulence intensity, measured in the longitudinal direction of the test section at 10 different downstream positions by a DISA 55D01 hot-wire anemometer, show the background turbulence generated by the wind tunnel to be very small. Mean velocity profiles in the wake of a sphere indicate rapid wake dissipation and show wake interaction with the wall boundary layer of the test section. Axisymmetric turbulence intensities are measured using an X-probe and two DISA 55D01 CTA units in both the Near and Far wakes of the sphere. Reynolds shear stresses are likewise measured and the wake development analyzed through the turbulent energy equation --Abstract, pages ii-iii

Numerical simulation of heat, mass, and momentum transfer in an atmospheric boundary layer

Considerable interest has developed in recent years to understand transport phenomena in thermally stratified boundary layers. More complete knowledge in this field is needed to improve the prediction of the diffusion of air pollutants in the lower atmosphere as well as in forecasting air-water circulation for weather conditions. The atmospheric boundary layer is modeled using the equations of continuity, momentum, energy, and concentration. Closure of this set of partial differential equations is hindered by the turbulence terms. Using turbulence kinetic energy, the system of equations is closed by internally determining the exchange coefficients of heat, mass, and momentum along with other atmospheric parameters. This approach makes it possible for the history of turbulent motion to be taken into account. Verification of this model is made by systematically comparing the numerical results with available wind tunnel data for neutral, stable, and unstable conditions. Application of the model is made to study the formation of advection fogs occurring over cold sea surfaces. However, the predicted results of liquid water and water vapor contents have yet to be verified with actual data obtained from field measurements --Abstract, page ii

Powered Wheelchair Platform for Assistive Technology Development

Literature shows that numerous wheelchair platforms, of various complexities, have been developed and evaluated for Assistive Technology purposes. However there has been little consideration to providing researchers with an embedded system which is fully compatible, and communicates seamlessly with current manufacturer's wheelchair systems. We present our powered wheelchair platform which allows researchers to mount various inertial and environment sensors, and run guidance and navigation algorithms which can modify the human desired joystick trajectory, so as to assist users with negotiating obstacles, and moving from room to room. We are also able to directly access other currently manufactured human input devices and integrate new and novel input devices into the powered wheelchair platform for clinical and research assessment

The Nature of the Variable Galactic Center Source IRS16SW

We report measurements of the light curve of the variable Galactic Center source IRS16SW. The light curve is not consistent with an eclipsing binary or any other obvious variable star. The source may be an example of a high mass variable predicted theoretically but not observed previously.Comment: 11 pages, 2 figures. Accepted by Ap

Social learning is central to innovation, in primates and beyond

AbstractMuch of the importance of innovation stems from its capacity to spread via social learning, affecting multiple individuals, thus generating evolutionary and ecological consequences. We advocate a broader taxonomic focus in the field of behavioral innovation, as well as the use of comparative field research, and discuss the unique conservation implications of animal innovations and traditions.This is the author accepted manuscript. The final version is available from Cambridge University Press via http://dx.doi.org/10.1017/S0140525X0700247