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Title: Reference Inflow Characterization for River Resource Reference Model (RM2)

Reference Inflow Characterization for River Resource Reference Model (RM2) Sandia National Laboratory (SNL) is leading an effort to develop reference models for marine and hydrokinetic technologies and wave and current energy resources. This effort will allow the refinement of technology design tools, accurate estimates of a baseline levelized cost of energy (LCoE), and the identification of the main cost drivers that need to be addressed to achieve a competitive LCoE. As part of this effort, Oak Ridge National Laboratory was charged with examining and reporting reference river inflow characteristics for reference model 2 (RM2). Published turbulent flow data from large rivers, a water supply canal and laboratory flumes, are reviewed to determine the range of velocities, turbulence intensities and turbulent stresses acting on hydrokinetic technologies, and also to evaluate the validity of classical models that describe the depth variation of the time-mean velocity and turbulent normal Reynolds stresses. The classical models are found to generally perform well in describing river inflow characteristics. A potential challenge in river inflow characterization, however, is the high variability of depth and flow over the design life of a hydrokinetic device. This variation can have significant effects on the inflow mean velocity and turbulence intensity experienced by stationary and bottom mounted hydrokinetic energy conversion more » devices, which requires further investigation, but are expected to have minimal effects on surface mounted devices like the vertical axis turbine device designed for RM2. A simple methodology for obtaining an approximate inflow characterization for surface deployed devices is developed using the relation umax=(7/6)V where V is the bulk velocity and umax is assumed to be the near-surface velocity. The application of this expression is recommended for deriving the local inflow velocity acting on the energy extraction planes of the RM2 vertical axis rotors, where V=Q/A can be calculated given a USGS gage flow time-series and stage vs. cross-section area rating relationship. « less
Authors:
Publication Date:
OSTI Identifier:OSTI ID: 1034378
Report Number(s):ORNL/TM-2011/360
TRN: US201204%%16
DOE Contract Number:DE-AC05-00OR22725
Resource Type:Technical Report
Research Org:Oak Ridge National Laboratory (ORNL)
Sponsoring Org:USDOE
Country of Publication:United States
Language:English
Subject: 17 WIND ENERGY; DESIGN; ENERGY CONVERSION; ORNL; RIVERS; ROTORS; STRESSES; TURBULENCE; TURBULENT FLOW; VELOCITY; VERTICAL AXIS TURBINES; WATER SUPPLY inflow characterization; riverine hydrokinetic resource; reference model