Date of Award

6-2012

Degree Name

MS in Aerospace Engineering

Department

Aerospace Engineering

Advisor

David Marshall

Abstract

This thesis was conducted as a contributing report to an ongoing NASA Research Announcement (NRA,#NNL07AA55C). The NRA investigates potential advanced commercial transport designs that could be utilized in the N+2 time frame (about 2025). The basis of the advanced design revolves around a heavily researched technology called Circulation Control that will be investigated through computational and wind tunnel methods for its feasibility in commercial aviation. The work of this thesis evaluates two potential meshing topologies when conducting CFD; Unstructured and Structured Meshing. Greatest challenges faced was handling the complexity of the computational model and capturing the correct physics that consisted of highly complex, 3-D, ow interactions. The complicated physics include mixing of subsonic/transonic uid, engine jet entrainment, and extreme lift from the circulation control jet ow. Results from this thesis showed that the Unstructured Meshing method applied introduced non-physical ow phenomenon not exhibited when applying Structured Meshing. The latter approach showed to be the superior method in its ability to capture the complicated physics of a circulation control aircraft. As promising the results were, it still remains inconclusive at this time. Further investigation is still required to completely evaluate the accuracy of the two meshing methodologies employed. At the time of this thesis, wind tunnel data was not available, thus remains a variable when evaluating the two different meshing topologies. In addition, this thesis was constrained by limited computational resources and software tools. Thus, the tribulations faced with Unstructured Meshing could have potentially resulted from these two external factors. Further investigation into alternative software tools that allow more user control should be considered next, in addition to having access to more computational resources. Although Unstructured Meshing showed to be inferior in this thesis, these remaining factors need to be eliminated before concluding Unstructured Meshing as not feasible for studying circulation control applications. Numerous studies[1, 2, 3] for 2-D circulation control applications have shown that Unstructured Meshing can be accurate, but the verdict is still out for 3-D models. This thesis yielded encouraging results and helps to aid further research in addressing this critical component for accurate numerical simulation.

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