@article {Ojeda_2017_AdaptiveCutCellConjugateHT,
	title = {An adaptive simplex cut-cell method for high-order discontinuous Galerkin discretizations of conjugate heat transfer problems},
	journal = {International Journal for Numerical Methods in Engineering},
	volume = {110},
	number = {4},
	year = {2017},
	pages = {350{\textendash}378},
	abstract = {In this paper, we present a solution framework for high-order discretizations of conjugate heat transfer problems on non-body-conforming meshes. The framework consists of and leverages recent developments in discontinuous Galerkin discretization, simplex cut-cell techniques, and anisotropic output-based adaptation. With the cut-cell technique, the mesh generation process is completely decoupled from the interface definitions. In addition, the adaptive scheme combined with the discontinuous Galerkin discretization automatically adjusts the mesh in each sub-domain and achieves high-order accuracy in outputs of interest. We demonstrate the solution framework through several multi-domained conjugate heat transfer problems consisting of laminar and turbulent flows, curved geometry, and highly coupled heat transfer regions. The combination of these attributes yield nonintuitive coupled interactions between fluid and solid domains, which can be difficult to capture with user-generated meshes. Copyright {\textcopyright} 2016 John Wiley \& Sons, Ltd.},
	keywords = {adaptation, conjugate heat transfer, cut cells, high-order},
	issn = {1097-0207},
	doi = {10.1002/nme.5362},
	url = {http://dx.doi.org/10.1002/nme.5362},
	author = {Ojeda, S M and Sun, H and Allmaras, S R and Darmofal, D L}
}
@article {Sun_2014_HODG_Interface,
	title = {An adaptive simplex cut-cell method for high-order discontinuous Galerkin discretizations of elliptic interface problems and conjugate heat transfer problems},
	journal = {Journal of Computational Physics},
	volume = {278},
	year = {2014},
	pages = {445 - 468},
	abstract = {In this paper we propose a new high-order solution framework for interface problems on non-interface-conforming meshes. The framework consists of a discontinuous Galerkin (DG) discretization, a simplex cut-cell technique, and an output-based adaptive scheme. We first present a DG discretization with a dual-consistent output evaluation for elliptic interface problems on interface-conforming meshes, and then extend the method to handle multi-physics interface problems, in particular conjugate heat transfer (CHT) problems. The method is then applied to non-interface-conforming meshes using a cut-cell technique, where the interface definition is completely separate from the mesh generation process. No assumption is made on the interface shape (other than Lipschitz continuity). We then equip our strategy with an output-based adaptive scheme for an accurate output prediction. Through numerical examples, we demonstrate high-order convergence for elliptic interface problems and CHT problems with both smooth and non-smooth interface shapes.},
	keywords = {adaptation},
	issn = {0021-9991},
	doi = {10.1016/j.jcp.2014.08.035},
	url = {http://www.sciencedirect.com/science/article/pii/S0021999114006032},
	author = {Sun, H and Darmofal, D L}
}
@booklet {Vision_2030_Final_Report_CRDL,
	title = {CFD Vision 2030 Study: A Path to Revolutionary Computational Aerosciences},
	journal = {NASA Technical Report},
	number = {NASA/CR-2014-218178},
	year = {2014},
	author = {Slotnick, J P and Khodadoust, A and Alonso, J J and Darmofal, D L and Gropp, W D and Lurie, E A and Mavriplis, D J}
}
@article {Slotnick_2014_EnivornmentCFD,
	title = {Enabling the environmentally clean air transportation of the future: a vision of computational fluid dynamics in 2030},
	journal = {Philosophical transactions. Series A, Mathematical, physical, and engineering sciences},
	volume = {372},
	number = {2022},
	year = {2014},
	month = {08},
	pages = {20130317},
	abstract = {As global air travel expands rapidly to meet demand generated by economic growth, it is essential to continue to improve the efficiency of air transportation to reduce its carbon emissions and address concerns about climate change. Future transports must be {\textquoteleft}cleaner{\textquoteright}and designed to include technologies that will continue to lower engine emissions and reduce community noise. The use of computational fluid dynamics (CFD) will be critical to enable the design of these new concepts. In general, the ability to simulate aerodynamic and reactive flows using CFD has progressed rapidly during the past several decades and has fundamentally changed the aerospace design process. Advanced simulation capabilities not only enable reductions in ground-based and flight-testing requirements, but also provide added physical insight, and enable superior designs at reduced cost and risk. In spite of considerable success, reliable use of CFD has remained confined to a small region of the operating envelope due, in part, to the inability of current methods to reliably predict turbulent, separated flows. Fortunately, the advent of much more powerful computing platforms provides an opportunity to overcome a number of these challenges. This paper summarizes the findings and recommendations from a recent NASA-funded study that provides a vision for CFD in the year 2030, including an assessment of critical technology gaps and needed development, and identifies the key CFD technology advancements that will enable the design and development of much cleaner aircraft in the future.},
	isbn = {1364-503X; 1471-2962},
	doi = {10.1098/rsta.2013.0317},
	url = {http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4095895/},
	author = {Slotnick, J P and Khodadoust, A and Alonso, J J and Darmofal, D L and Gropp, W D and Lurie, E A and Mavriplis, D J and Venkatakrishnan, V}
}
@conference {Sun_2013_Interface,
	title = {An adaptive simplex cut-cell method for high-order discontinuous Galerkin discretizations of multi-material and multi-physics problems},
	booktitle = {AIAA conference paper},
	number = {2013{\textendash}2443},
	year = {2013},
	author = {Sun, H and Darmofal, D L}
}
@mastersthesis {Sun_2013_PhD,
	title = {A Robust Simplex Cut-Cell Method for Adaptive High-Order Finite Element Discretizations of Aerodynamics and Multi-Physics Problems},
	year = {2013},
	month = {August},
	school = {Massachusetts Institute of Technology},
	type = {phd},
	address = {Department of Aeronautics and Astronautics},
	url = {http://hdl.handle.net/1721.1/85764},
	author = {Sun, H}
}
@conference {Sun_2013_Robust3DCutCells,
	title = {A robust simplex cut-cell method for high-order discontinuous Galerkin discretizations of three-dimensional aerodynamic problems},
	booktitle = {AIAA conference paper},
	number = {2013{\textendash}3082},
	year = {2013},
	month = {June},
	author = {Sun, H and Darmofal, D L and Haimes, R}
}
@article {Sun_TriangleShapeImpact_JCP_2012,
	title = {On the impact of triangle shapes for boundary layer problems using high-order finite element discretization},
	journal = {Journal of Computational Physics},
	volume = {231},
	number = {2},
	year = {2012},
	pages = {541{\textendash}557},
	doi = {10.1016/j.jcp.2011.09.018},
	author = {Sun, H and Darmofal, D L and Haimes, R}
}
@mastersthesis {Sun_2009_Adaptation,
	title = {Impact of Triangle Shapes Using High-order Discretizations and Direct Mesh Adaptation for Output Error},
	year = {2009},
	school = {Massachusetts Institute of Technology},
	type = {masters},
	address = {Computation for Design and Optimization Program},
	url = {http://hdl.handle.net/1721.1/54215},
	author = {Sun, H}
}
@article {Sidwell_2005_ImpactBladetoBladeVariabilityCooling,
	title = {The impact of blade-to-blade flow variability on turbine blade cooling performance},
	journal = {Journal of Turbomachinery},
	volume = {127},
	number = {4},
	year = {2005},
	pages = {763{\textendash}770},
	abstract = {The focus of this paper is the impact of manufacturing variability on turbine blade cooling flow and, subsequently, its impact on oxidation life. A simplified flow network model of the cooling air supply system and a row of blades is proposed. Using this simplified model, the controlling parameters which affect the distribution of cooling flow in a blade row are identified. Small changes in the blade flow tolerances (prior to assembly of the blades into a row) are shown to have a significant impact on the minimum flow observed in a row of blades resulting in substantial increases in the life of a blade row. A selective assembly method is described in which blades are classified into a low-flow and a high-flow group based on passage flow capability (effective areas) in life-limiting regions and assembled into rows from within the groups. Since assembling rows from only high-flow blades is equivalent to raising the low-flow tolerance limit, high-flow blade rows will have the same improvements in minimum flow and life that would result from more stringent tolerances. Furthermore, low-flow blade rows are shown to have minimum blade flows which are the same or somewhat better than a low-flow blade that is isolated in a row of otherwise higher-flowing blades. As a result, low-flow blade rows are shown to have lives that are no worse than random assembly from the full population. Using a higher fidelity model for the auxiliary air system of an existing jet engine, the impact of selective assembly on minimum blade flow and life of a row is estimated and shown to be in qualitative and quantitative agreement with the simplified model analysis.},
	isbn = {0889-504X},
	doi = {10.1115/1.2019247},
	author = {Sidwell, V and Darmofal, D L}
}
@mastersthesis {Sidwell_2004_Phd,
	title = {On the Impact of Variability and Assembly on Turbine Blade Cooling Flow and Oxidation Life},
	year = {2004},
	school = {Massachusetts Institute of Technology},
	type = {phd},
	address = {Department of Aeronautics and Astronautics},
	url = {http://hdl.handle.net/1721.1/17814},
	author = {Sidwell, V}
}
@conference {Darmofal_2002_ConceptMaps,
	title = {Using concept maps and concept questions to enhance conceptual understanding},
	booktitle = {Proceedings of the 2002 American Society for Engineering Education Annual Conference \& Exposition},
	year = {2002},
	keywords = {education},
	author = {Darmofal, D L and Soderholm, D H and Brodeur, D R}
}
@article {Darmofal_1999_RobustMultigrid_LPC_SC,
	title = {A Robust Multigrid Algorithm for the Euler Equations with Local Preconditioning and Semi-coarsening},
	journal = {Journal of Computational Physics},
	volume = {151},
	number = {2},
	year = {1999},
	pages = {728 - 756},
	abstract = {A semi-coarsened multigrid algorithm with a point block Jacobi, multi-stage smoother for second-order upwind discretizations of the two-dimensional Euler equations which produces convergence rates independent of grid size for moderate subsonic Mach numbers is presented. By modification of this base algorithm to include local preconditioning for low Mach number flows, the convergence becomes largely independent of grid size and Mach number over a range of flow conditions from nearly incompressible to transonic flows, including internal and external flows. A local limiting technique is introduced to increase the robustness of preconditioning in the presence of stagnation points. Computational timings are made showing that the semi-coarsening algorithm requiresO(N) time to lower the fine grid residual six orders of magnitude, whereNis the number of cells. By comparison, the same algorithm applied to a full-coarsening approach requiresO(N3/2) time, and, in nearly all cases, the semi-coarsening algorithm is faster than full coarsening with the computational savings being greatest on the finest grids.},
	issn = {0021-9991},
	doi = {10.1006/jcph.1999.6216},
	url = {http://www.sciencedirect.com/science/article/pii/S0021999199962162},
	author = {Darmofal, D L and Siu, K}
}
@mastersthesis {Srinivasan_1998_SM,
	title = {Multidiscipinary Simulation of a Flexible Hydrofoil},
	year = {1998},
	school = {Texas A\&M University},
	type = {masters},
	address = {Department of Aerospace Engineering},
	author = {Srinivasan, V}
}
@mastersthesis {Siu_1998_SM,
	title = {A Robust, Locally Preconditioned Multigrid Algorithm for the Euler Equations},
	year = {1998},
	school = {Texas A\&M University},
	type = {masters},
	address = {Department of Aerospace Engineering},
	author = {Siu, K}
}
@mastersthesis {Singh_1998_SM,
	title = {Software Development for an Improved Particle Image Velocimetry},
	year = {1998},
	school = {Texas A\&M University},
	type = {masters},
	address = {Department of Aerospace Engineering},
	author = {Singh, K D}
}
@article {Darmofal_1996_LocalPreconditioningEigenvectors,
	title = {The Importance of Eigenvectors for Local Preconditioners of the Euler Equations},
	journal = {Journal of Computational Physics},
	volume = {127},
	number = {2},
	year = {1996},
	pages = {346 - 362},
	abstract = {The design of local preconditioners to accelerate the convergence to a steady state for the compressible Euler equations has so far been solely based on eigenvalue analysis. However, numerical evidence exists that the eigenvector structure also has an influence on the performance of preconditioners and should therefore be included in the design process. In this paper, we present the mathematical framework for the eigenvector analysis of local preconditioners for the multi-dimensional Euler equations. The non-normality of the preconditioned system is crucial in determining the potential for transient amplification of perturbations. Several existing local preconditioners are shown to possess a highly non-normal structure for low Mach numbers. This non-normality leads to significant robustness problems at stagnation points. A modification to these preconditioners which eliminates the non-normality is suggested, and numerical results are presented showing the marked improvement in robustness.},
	issn = {0021-9991},
	doi = {10.1006/jcph.1996.0180},
	url = {http://www.sciencedirect.com/science/article/pii/S0021999196901801},
	author = {Darmofal, D L and Schmid, P J}
}
