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General Kenneth Nichols and the Manhattan Project
Nichols
The Oak Ridger has published the latest in a series of articles about General Kenneth D. Nichols, the Manhattan Project, and the 1954 Atomic Energy Act. The series has been produced by Nichols’ grandniece Barbara Rogers Scollin and Oak Ridge (Tenn.) city historian David Ray Smith. Gen. Nichols (1907–2000) was the district engineer for the Manhattan Engineer District during the Manhattan Project.
As Smith and Scollin explain, Nichols “had supervision of the research and development connected with, and the design, construction, and operation of, all plants required to produce plutonium-239 and uranium-235, including the construction of the towns of Oak Ridge, Tennessee, and Richland, Washington. The responsibility of his position was massive as he oversaw a workforce of both military and civilian personnel of approximately 125,000; his Oak Ridge office became the center of the wartime atomic energy’s activities.”
Iztok Tiselj, Cedric Flageul, Jure Oder (Jožef Stefan Inst), invited
Proceedings | Advances in Thermal Hydraulics 2018 | Orlando, FL, November 11-15, 2018 | Pages 1050-1065
The paper discusses the most accurate methods for description of turbulent flows: computationally very expensive Direct Numerical Simulation (DNS) and, slightly less accurate and slightly less expensive, Large Eddy Simulation (LES) method. Both methods have found the way into the nuclear thermal hydraulics as tools for studies of the fundamental mechanisms of turbulence and turbulent heat transfer. In the first Section of the paper, both methods are briefly introduced in parallel with the basic properties of the turbulent flows. The focus is on DNS method, the so-called quasi-DNS approach, and the coarsest turbulence modelling approach discussed in this work, which is still on the very small scale, wall-resolved LES. Other, coarser turbulence modeling approaches (such as wall-modelled LES, RANS/LES hybrids, or RANS) are beyond the scope of the present paper. Section 2. answers the question: "How do DNS and LES methods work?", with a short discussion of the computational requirements, numerical approaches and computational tools. Section 3. is about the interpretation of the DNS and LES results and statistical uncertainties. Sections 4. and 5. give some examples of the DNS and wall-resolved LES results relevant for nuclear thermal hydraulics. The last section lists the conclusions and some of the challenges, which might be tackled with the most accurate techniques like DNS and LES.