Free convection laminar boundary layers in oscillatory flow

The effect of harmonic oscillations in the magnitude of the surface temperature on the free-convection laminar velocity and temperature boundary layers on a flat plate is analysed. Low-and high-frequency solutions are developed separately. The results obtained are in striking contrast to the corresponding results for forced-convection flows.

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Free Convection From a Vertical Flat Plate With Step Discontinuities in Surface Temperature

Journal of Heat Transfer ◽

10.1115/1.3614371 ◽

1967 ◽

Vol 89 (3) ◽

pp. 244-249 ◽

Cited By ~ 41

Author(s):

A. A. Hayday ◽

D. A. Bowlus ◽

R. A. McGraw

Keyword(s):

Free Convection ◽

Surface Temperature ◽

Flat Plate ◽

Boundary Layers ◽

Theoretical Basis ◽

Vertical Plate ◽

Strongly Coupled ◽

Laminar Boundary Layers ◽

Coupled Equations ◽

Vertical Flat Plate

The paper explores a numerical method for the solution of strongly coupled equations governing nonsimilar flows in laminar boundary layers. The analysis deals specifically with nonsimilar free convection from a vertical plate suspended in air, the nonsimilarity of the flow being generated by step discontinuities in surface temperatures. Results presented herein compare favorably with and form a theoretical basis for the experiments of Schetz and Eichhorn.

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FREE-CONVECTION LAMINAR BOUNDARY LAYERS IN OSCILLATORY FLOW

AIAA Journal ◽

10.2514/3.1683 ◽

1963 ◽

Vol 1 (4) ◽

pp. 937-937 ◽

Cited By ~ 4

Author(s):

RATTAN SAGAR NANDA ◽

VISHNOO PRASAD SHARMA

Keyword(s):

Free Convection ◽

Boundary Layers ◽

Oscillatory Flow ◽

Laminar Boundary Layers

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Skin friction and surface temperature of an insulated flat plate fixed in a fluctuating stream

Journal of Fluid Mechanics ◽

10.1017/s0022112071000466 ◽

1971 ◽

Vol 46 (1) ◽

pp. 165-175 ◽

Cited By ~ 3

Author(s):

Hiroshi Ishigaki

Keyword(s):

Boundary Layer ◽

Surface Temperature ◽

Flat Plate ◽

Skin Friction ◽

High Frequency ◽

Energy Equation ◽

Oscillation Amplitude ◽

Flow Oscillation ◽

Velocity Amplitude ◽

The Mean

The time-mean skin friction of the laminar boundary layer on a flat plate which is fixed at zero incidence in a fluctuating stream is investigated analytically. Flow oscillation amplitude outside the boundary layer is assumed constant along the surface. First, the small velocity-amplitude case is treated, and approximate formulae are obtained in the extreme cases when the frequency is low and high. Next, the finite velocity-amplitude case is treated under the condition of high frequency, and it is found that the formula obtained for the small-amplitude and high-frequency case is also valid. These results show that the increase of the mean skin friction reduces with frequency and is ultimately inversely proportional to the square of frequency.The corresponding energy equation is also studied simultaneously under the condition of zero heat transfer between the fluid and the surface. It is confirmed that the time-mean surface temperature increases with frequency and tends to be proportional to the square root of frequency. Moreover, it is shown that the timemean recovery factor can be several times as large as that without flow oscillation.

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