Date of Award
Master of Science (MS)
In recent years there has been resurgence of interest by aerospace industry and NASA in supersonic transport aircraft. In recent studies, the emphasis has been on shape optimization of supersonic plane to reduce the acoustic signature of sonic boom resulting from the supersonic aircraft at high altitude in cruise flight. Because of the limitations of in-flight testing and cost of laboratory scale testing, CFD technology provides an attractive alternative to aid in the design and optimization of supersonic vehicles. In last decade, the predictive capability of CFD technology has significantly improved because of substantial increase in computational power, which allows for treatment of more complex geometries with larger meshes, better numerical algorithms and improved turbulence models for Reynolds-averaged Navier-Stokes (RANS) to reduce the predictive error. As computational power continues to increase, numerical optimization techniques have been combined with CFD to further aid in the design process.
In this thesis, two cases from the recent AIAA Sonic Boom Prediction Workshop have been simulated and one of them is optimized to reduce the sonic boom signature. The AIAA Sonic Boom Prediction Workshop has three models for the study of predicting sonic boom signatures and sonic boom propagation; in this thesis the Lockheed SEEB-ALR and 69 Degree Delta Wing-Body models are considered. The grid generation is conducted by ANSYS ICEM. Flow calculations are performed with ANSYS Fluent using the compressible Euler equations. Excellent agreement between the computed pressure distributions and experimental results at all positions of the models is obtained. Shape optimization of the SEEB-ALR axisymmetric body to minimize the sonic boom signature is then performed using a genetic algorithm (GA). The optimized shape shows decrease in the strength of the sonic boom signature. The results presented in thesis demonstrate that CFD can be accurately and effectively employed for shape optimization of a supersonic airplane to minimize the boom signature.
David Peters Swami Karunamoorthy