As aerospace vehicles progress into the hypersonic regime, new challenges face the design engineer. Successful design of this type of vehicle clearly requires the capability to analyze high-speed aerodynamics, propulsion systems involving supersonic mixing and combustion, high-temperature thermal protection systems, airframes under extreme loads, and control systems capable of stabilizing the vehicle in a broad range of flight conditions. What is less readily apparent is that in the hypersonic regime, these analyses are tightly coupled and the interactions among them cannot be neglected. Small changes in shape due to pressure and thermal loading can significantly change the aerodynamics, which in turn changes the efficiency of the propulsion system and the aerodynamic and thermal loads. While traditional engineering approaches often attempt to separate analyses into disciplines, current vehicles demand that analyses be performed in a multi-disciplinary manner. For the next generation of vehicles, failure to achieve an early and accurate representation of the physics within and among disciplines can easily result in failure of the program.
In a process with efficient integration of disciplinary analyses, the time spent within the disciplinary analyses becomes the primary cost consideration. In fact, it is often the case that one discipline significantly affects the time required for the entire process. The viability of a system for aerothermodynamic, servo, thermal, elastic, propulsive (ASTEP) couple analysis is highly dependent on the selection of an accurate and efficient aerothermodynamic solver. Computational Fluid Dynamic (CFD) methods required for accurately representing the relevant physics have traditionally been very time consuming. Recent methods providing more efficient solutions enable a viable CFD based ASTEP process. In the ASTEP system, modern CFD methods will allow for a tool that is both highly accurate and computationally inexpensive. Taking full advantage of the approaches used in developing the IHAT multidisciplinary analysis/optimization toolkit, this core capability of aerothermal analysis is integrated into an automated ASTEP software product. This product accurately represents aerothermodynamic pressure and temperature, propulsive force and heat, ablation thickness, and structural deflection. The interactions of these effects is represented in an algorithm that iterates until a solution is reached which represents the relevant physics within and among the disciplines.