Date of Award

Fall 2005

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Mechanical & Aerospace Engineering

Program/Concentration

Aerospace Engineering

Committee Director

Osama A. Kandil

Committee Member

Brett Newman

Committee Member

Oktay Baysal

Call Number for Print

Special Collections; LD4331.E535 O96 2005

Abstract

Sonic Booms of two different bodies, a double cone configuration and a modified F-SE aircraft, are predicted using Euler solvers for the near field, and a Full Potential Propagation method for the far field. The problem is considered inviscid since viscous effects in high Reynolds number flows are negligible in Sonic Boom propagation. To enhance the accuracy of the predictions, elaborate shock fitting and grid adaptation routines are developed that can handle complicated shock topologies. The far field propagation code using the full potential equation is the first three-dimensional computational fluid dynamics code in literature that can march the solution through the atmosphere with atmospheric changes in temperature and pressure taken into account. The non-linearity and non-axisymmetric of the Full Potential propagation code are its superiorities against the available "state-of-the-art" prediction methods that utilize the linear "ray-tracing" approach. Since the shocks in the far field are weak, and the wake of the body is avoided by the use of a "hollow" conical grid, the flow properties can be said to be isentropic and irrotational. This assumption enables the use of the full potential equation to compute the far field flow.

Recent efforts to reduce sonic boom noise and enable supersonic aircraft to fly over land have concluded that a "shaped" sonic boom will have lower noise than a regular "N-wave" type. Such shaped sonic booms are produced by carefully tailoring the shape and area of the aircraft to redistribute the lift. The resultant shock topology if more complicated than a regular design, and non-linear and cross-flow effects become important in the evolution of this complicated wave structure. Hence there is a growing need for non-linear methodologies in sonic boom prediction. This thesis presents such a method, with comparisons to experimental results for the double cone and for the modified F-SE aircraft. There is excellent agreement between computational and experimental results.

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DOI

10.25777/z5ht-gm57

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