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Fluid mechanics experiments in oscillatory flow. Volume 1

Technical Report ·
DOI:https://doi.org/10.2172/10181069· OSTI ID:10181069
; ;  [1]
  1. Univ. of Minnesota, Minneapolis, MN (United States)

Results of a fluid mechanics measurement program is oscillating flow within a circular duct are present. The program began with a survey of transition behavior over a range of oscillation frequency and magnitude and continued with a detailed study at a single operating point. Such measurements were made in support of Stirling engine development. Values of three dimensionless parameters, Re{sub max}, Re{sub W}, and A{sub R}, embody the velocity amplitude, frequency of oscillation and mean fluid displacement of the cycle, respectively. Measurements were first made over a range of these parameters which included operating points of all Stirling engines. Next, a case was studied with values of these parameters that are representative of the heat exchanger tubes in the heater section of NASA`s Stirling cycle Space Power Research Engine (SPRE). Measurements were taken of the axial and radical components of ensemble-averaged velocity and rms-velocity fluctuation and the dominant Reynolds shear stress, at various radial positions for each of four axial stations. In each run, transition from laminar to turbulent flow, and in reverse, were identified and sufficient data was gathered to propose the transition mechanism. Models of laminar and turbulent boundary layers were used to process the data into wall coordinates and to evaluate skin friction coefficients. Such data aids in validating computational models and is useful in comparing oscillatory flow characteristics to those of fully-developed steady flow. Data were taken with a contoured entry to each end of the test section and with flush square inlets so that the effects of test section inlet geometry on transition and turbulence are documented. The following is presented in two-volumes. Volume I contains the text of the report including figures and supporting appendices. Volume II contains data reduction program listings and tabulated data (including its graphical presentation).

Research Organization:
National Aeronautics and Space Administration, Cleveland, OH (United States). Lewis Research Center
Sponsoring Organization:
USDOE, Washington, DC (United States); National Aeronautics and Space Administration, Washington, DC (United States)
DOE Contract Number:
AI03-86SF16310
OSTI ID:
10181069
Report Number(s):
NASA-CR--189127; ON: DE94051209
Country of Publication:
United States
Language:
English