Browsing by Subject "Explosions"
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Item Atmospheric density fluctuations due to solar modulation & orbital debris modeling(Texas Tech University, 2006-05) Noll, BenjaminThe majority of manmade debris in Earths orbit is related to the breakup of satellites and their propulsion systems. Since the first major satellite breakup in 1961, there has been increasing concern about the hazards posed by orbital debris. Some orbits may contain very large numbers of objects of varying shapes and sizes, while others contain very few. Currently there are a number of models that are used to predict the future debris environment. The two greatest sources of uncertainty in these models are atmospheric drag in low orbits, and debris fragmentation. The atmospheric drag on orbiting debris varies as the atmosphere expands and contracts due to solar modulation. Fragmentation models are vital for the estimation of current and future debris populations. Current fragmentation models are built on empirical fits to experimental data, and observed debris populations. While these models adequately describe large debris objects, there is a large amount of uncertainty with respect to small sized debris. Therefore, there is an ongoing effort to develop alternative models that are able to make predictions based on physical arguments.Item Item Physically based simulation of explosions(Texas A&M University, 2005-08-29) Roach, Matthew DouglasThis thesis describes a method for using physically based techniques to model an explosion and the resulting side effects. Explosions are some of the most visually exciting phenomena known to humankind and have become nearly ubiquitous in action films. A realistic computer simulation of this powerful event would be cheaper, quicker, and much less complicated than safely creating the real thing. The immense energy released by a detonation creates a discontinuous localized increase in pressure and temperature. Physicists and engineers have shown that the dissipation of this concentration of energy, which creates all the visible effects, adheres closely to the compressible Navier-Stokes equation. This program models the most noticeable of these results. In order to simulate the pressure and temperature changes in the environment, a three dimensional grid is placed throughout the area around the detonation and a discretized version of the Navier-Stokes equation is applied to the resulting voxels. Objects in the scene are represented as rigid bodies that are animated by the forces created by varying pressure on their hulls. Fireballs, perhaps the most awe-inspiring side effects of an explosion, are simulated using massless particles that flow out from the center of the blast and follow the currents created by the dissipating pressure. The results can then be brought into Maya for evaluation and tweaking.