Nonisothermal turbulent boundary-layer adverse pressure gradient large scale thermal structure measurements

Journal Article · Sat Jan 01 04:00:00 EST 1994 · Journal of Thermophysics and Heat Transfer

DOI:https://doi.org/10.2514/3.502· OSTI ID:45861

Bagheri, N; White, B R; Lei, T ^[1]

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1. California Maritime Academy, Vallejo, CA (United States)

Hot-wire anemometry measurements in an incompressible turbulent boundary-layer flow over a heated flat plate under equilibrium adverse-pressure-gradient conditions (beta = 1.8) were made for two different temperature difference cases (10 and 15 C) between the wall and the freestream. Space-time correlations of temperature fluctuations (T`) were obtained with a pair of subminiature temperature fluctuation probes. The mean convection velocities, the mean inclination angles, and coherence characteristics of the T` large-scale structure were determined. The present temperature structures measurements for a nonisothermal boundary layer are compared to the zero-pressure-gradient case with identical temperature differences previously reported, in which the mean convection velocity of the T` structure was a function of position y(sup +) and independent of the limited temperature-difference cases tested. The three major findings of the present study, as compared to the zero-pressure-gradient case, are (1) the mean convection speed of the T` structure under beta = 1.8 pressure-gradient conditions was found to be substantially lower in the logarithmic core region than the zero-pressure-gradient case. Additionally, the mean convection speed is felt by the authors to be a function of pressure-gradient parameter beta; (2) the mean inclination angle of the T` structure to the wall under the adverse-pressure-gradient flow was 32 deg, which compares favorably to the 30-deg value of the zero-pressure-gradient case; and (3) the limited data suggests that the mean convection velocity of the T` structure is a function of y(sup +) and independent of the limited temperature-difference cases tested. 11 refs.

• Sponsoring Organization: USDOE
• OSTI ID: 45861
• Journal Information: Journal of Thermophysics and Heat Transfer, Journal Name: Journal of Thermophysics and Heat Transfer Journal Issue: 1 Vol. 8; ISSN 0887-8722; ISSN JTHTEO
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
FLOW RATE
PRESSURE DEPENDENCE
PRESSURE GRADIENTS
TEMPERATURE DISTRIBUTION
TURBULENT FLOW