Seismic Detection of Tornadoes-At the present time the only generally accepted method for detecting when a tornado is on the ground is human observation. Based on actual seismic signals combined with eyewitness testimony, there i s very strong evidence to indicate that a tornado in contact with the ground produces significant tornadic seismic vibrations (TSV) both long-period and short-period. The proposed program is designed to lead to a totally new way of detecting when a torna do is on the ground, based on tornadic seismic signal (TSS) derived from the TSV. This seismic tornado detector (STD) system has considerable potential for use by government agencies for the protection of the general populace, a s well as for use by the individual citizen for personal safety within the home.
Calculation of Surface Pressure Fluctuations Based on Time-Averaged Turbulent Flow- The solution to the equation governing the intensity of turbulent pressure fluctuations for flow over a flat plate has been written in a form suitable for numerical computation. The solution involves Green functions and six-fold integration of certain properties of the mean flow field. A computational algorithm, e ntitled SURPRESS, has been developed.
Application of Fractional Calculus to Noise Simulation-Based on the principles of fractional calculus we developed the numerical procedure for generating discrete time series with irrational spectral characteristics. These numerical procedures have been incorporated into the software program, NOISE. Based on a review of a variety of different noise processes, the longitudinal component of atmospheric turbulent gusts was selected as the candidate noise process to simulate. A series of test runs were carried out to demonstrate the capability of the NOISE program to generate realistic simulations of such a process. Based on spectral analysis the output time series appeared to match the theoretical von Karman spectrum. Based on statistical analysis the output appeared to be characterized by a Gaussian probability density function. Te sts revealed that the NOISE numerical procedure converged quite satisfactorily with quite accurate results, without the need for an excessive number of terms or extremely small tolerances.
Audio-Visual Initial Debug (AVID) Method for Computer Software-The Audio- Visual Initial Debug (AVID) method is a first-line software development tool for locating errors in new source code. The concept involves using a computer speech synthesizer connected to the terminal to provide an audio playback of the source code while the programmer visually follows his original handwritten text. Certain stand ard and user-defined key words are pronounced while all other symbols are spelled character by character. Speech is accomplished via inexpensive, phoneme-based, add-on equipment with essentially unlimited vocabulary. Speaking rate, volume, frequency, and intonation are user-controlled. In addition the AVID software allows the user to position control at any line in his text and move in any direction.
Advanced Space Shuttle Turbulence Simulation-The effects of atmospheric turbulence in both horizontal and near-horizontal flight, during the return of the Space Shuttle, are important for determining design, control, and "pilot-in-the-loop" effects. A non-recursive model (based on von Karman spectra) for atmospheric turbulence along the flight path of the Shuttle Orbiter was developed which provided for simulation of instantaneous vertical and horizontal gusts at the veh icle center-of-gravity, and also for simulation of instantaneous gust gradients. Based on this model the time series for both gusts and gust gradients were generated and stored on a series of magnetic tapes which are entitled Shuttle Simulation Turbulence Tapes (SSTT). The time series were designed to represent atmospheric turbulence from ground level to an alti tude of 120,000 meters.
Processing and Displaying Atmospheric Phenomena-This award resulted from the development of the PEC (Potential in an Electrostatic Cloud) computer program. This program was designed for calculating potential and the components of the electric field which are produced by the distributed charge within a cylindrically shaped cloud model. The program also includes graphics capabilities through the use of standard x-y plots, vector plots, and contour plots. The cloud model is composed of individual horizontal layers or zones of finite thickness, each with a constant charge density. The height of the base of the cloud may be any distance above the ground. Due to the shape of the cloud model, cylindrical coordinates have been utilized. However, the potential for some general point is independent of angular position due to axisymmetr y, and thus the angular position is not included in most of the input options.
Contour Plotting of Lightning Strikes-This technique was an original idea developed by our personnel. This idea led to the NSSL Lightning Data Program. This program generates an x-y plot of lightning strikes over a given period of time, sums the number of occurrences in pre-determined unit areas, and then generates a contour plot based on the calculated frequencies. The basic purpose of the program is to correlate lightning strike locations with storm cells position(s). The basic approach in the development of the program involved computing the number density of strikes (per unit area) and generating contour maps representing lines of constant number density. Our contour plotting routine was incorporated into existing software to generate the necessary contour plots.