Hello, A new project on the LCRC cluster has been requested. Please forward the information on to the LCRC Allocation sub-committee. Applicant's name: Justin Walker Applicant's institution: ANL Applicant's division: MCS Project Name: rod_bundle Project title: Thermal hydraulics for tight rod bundle lattices Associated funding: Other Systems: MCS general compute servers, cosmea - unlimited Intrepid - 35525491.6 cpu hours Science: This project is an auxiliary project in support of computational fluid dynamics(CFD) calculations of the thermal hydraulics of nuclear reactor cores. Within the framework of the spectral element method, we are studying the effects of different large eddy simulation(LES) models and resolution levels on the fidelity of turbulent flow calculations. In particular, we would like to know what level of resolution is required to obtain data useable to the engineering and science communities. It is important to investigate this on smaller problems before moving to a full scale calculation on a machine like Intrepid, since it allows us to achieve better results while we push the limits of CFD. Project description: We plan to perform LES and direct numerical simulation(DNS) of turbulent flow past a single rod in a periodic domain, corresponding to a rod in an infinite lattice. This model problem closely resembles the conditions for a central rod in the large arrays found in nuclear reactor designs. From these calculations, we hope to obtain a measure of the resolution required to match published experimental results of important quantities such as the Reynolds stresses and wall shear stress. To perform these calculations, we will be using the computational fluid dynamics solver nek5000 which is based on the spectral element method. This code has already been validated and shown to scale very well by use on this machine as well as ALCF's Intrepid and MIRA. See http://nek5000.mcs.anl.gov/index.php/Scaling. We will be running jobs of no more than 8 nodes, since we've experienced problems with greater numbers of nodes on this machine. Job sizes will primary be about 1GB per core and run for about 60 hours each. Some will require longer, up to 120 hours. There will be up to four project members but the primary use of the allocation will be by just one of the members. Project URL: Requested allocation: 200000 Q1: 50000 Q2: 50000 Q3: 50000 Q4: 50000 Justification: The requester has used undetermined amount hours of their initial startup project. In addition to approving an initial amount, please specify a Category and Subcategory for this project. For a list of the current selection of approved categories, please see: https://wiki.lcrc.anl.gov/wiki/Processes/Categories Once the Allocation committee has approved the project, please go to the Project Management page to create it: https://accounts.lcrc.anl.gov/projects.php Thank You, The LCRC Accounts System