A very competitive atmosphere shrouds the current aerospace market, which includes commercial and military airplanes, missiles and launch vehicles. As a result, designers now must optimize their vehicle's performance while maintaining or even reducing respective costs. However, vehicles operating at a high altitude experience a number of flow phenomena, which typically hamper the vehicle's overall performance. And because the effects of these phenomena are not fully known, designers are generally forced to predict a worst possible case of the phenomenon occurring on their vehicles and design to medicate those effects. The immediate result is a decrease in the vehicle's capabilities and an increase in production cost. Lockheed Martin is currently developing the next generation of Atlas Launch Vehicle, the Atlas V, to compete in this market. And therefore, must strive to maintain the reliability and performance success from the Atlas line of launch vehicles. On board instrumentation and wind tunnel testing on a previous configuration, the Atlas IIIA, indicates that a phenomenon known as Plume Induced Flow Separation (PIFS) is occurring on the Atlas Rocket. PIFS allows the re-circulation of hot thrust gases into regions of separated flow along the vehicle's surface, increasing surface heat transfer rates on the vehicle. Without the ability to perform a complete three-dimensional analysis on the effects of the PIFS phenomenon, Lockheed Martin must default to a worst-case scenario for PIFS in the design of protecting their vehicle. This requires a large portion of the aft section of the vehicle to be covered in thermal protection, increasing the overall weight, while decreasing the overall vehicle capability. The main objective of this research study was to perform a numerical investigation of the PIFS phenomenon occurring on an Atlas IIIA Launch Vehicle. The Numerical simulation of the Atlas IIIA/PIFS flowfield has been performed at a steady-state point along the vehicle's flight path. And the numerical prediction of the occurrence, extent and effects of the phenomenon will be presented to Lockheed Martin to used to possibly optimize the design of their Atlas Launch Vehicle.
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