scholarly journals Unsteady Boundary Layers on a Flat Plate Disturbed by Periodic Wakes: Part I — Measurement of Wake-Affected Heat Transfer and Wake-Induced Transition Model

1994 ◽  
Author(s):  
K. Funazaki
Keyword(s):  
Heat Transfer ◽  
Flat Plate ◽  
Rotating Disk ◽  
Circular Cylinders ◽  
Transition Model ◽  
Time Diagram ◽  
Test Conditions ◽  
Intermittency Factor ◽  
Unsteady Boundary Layers ◽  
Good Agreement

Measurements of wake-affected heat transfer distributions on a flat plate are made by use of a wake generator that consists of a rotating disk and several types of circular cylinders. The main purpose of this study is to construct a wake-induced transition model in terms of an intermittency factor, considering the evolution of the wake-induced turbulent region, a so-called turbulent patch in a distance-time diagram. A comparison between the proposed transition model and the measured heat transfer data reveals that the transition model yields good agreement with the measured data of all test conditions in this study.

Unsteady Boundary Layers on a Flat Plate Disturbed by Periodic Wakes: Part I—Measurement of Wake-Affected Heat Transfer and Wake-Induced Transition Model

1996 ◽  
Vol 118 (2) ◽  
pp. 327-336 ◽  
Author(s):  
K. Funazaki
Keyword(s):  
Heat Transfer ◽  
Flat Plate ◽  
Rotating Disk ◽  
Measured Data ◽  
Transition Model ◽  
Time Diagram ◽  
Test Conditions ◽  
Intermittency Factor ◽  
Unsteady Boundary Layers ◽  
Good Agreement

Measurements of wake-affected heat transfer distributions on a flat plate are made by use of a wake generator that consists of a rotating disk and several types of circular cylinder. The main purpose of this study is to construct a wake-induced transition model in terms of an intermittency factor, considering the evolution of the wake-induced turbulent region, a so-called turbulent patch in a distance–time diagram. A comparison between the proposed transition model and the measured heat transfer data reveals that the transition model yields good agreement with the measured data of all test conditions in this study.

scholarly journals A Theory for Wake-Induced Transition

1989 ◽  
Author(s):  
R. E. Mayle ◽  
K. Dullenkopf
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Turbulent Flow ◽  
Flat Plate ◽  
Free Stream ◽  
Plate Boundary ◽  
Transition Model ◽  
Model Comparisons ◽  
Turbulent Wakes ◽  
Flat Plate Boundary Layer

A theory for transition from laminar to turbulent flow as the result of unsteady, periodic passing of turbulent wakes in the free stream is developed using Emmons’ transition model. Comparisons made to flat plate boundary layer measurements and airfoil heat transfer measurements confirm the theory.

Wind-Related Heat Transfer Coefficient for Flat-Plate Solar Collectors

1987 ◽  
Vol 109 (2) ◽  
pp. 108-110 ◽  
Author(s):  
S. Shakerin
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Flat Plate ◽  
Separation Bubble ◽  
Convective Heat Transfer Coefficient ◽  
Leading Edge ◽  
The Heat Transfer Coefficient ◽  
Good Agreement

Experiments were performed to evaluate the convective heat transfer coefficient for a flat plate mounted in a wooden model of a roof of a building. The experiments were carried out in a closed-circuit wind tunnel and included parametric adjustments of the roof tilt and Reynolds number, based on the length of the plate. The roof tilt was set at 0, 30, 45, 60, and 90 degrees and the Reynolds number ranged from 58,000 to 250,000. A transient, one lump, thermal approach was used for heat transfer calculations. Due to a separation bubble at the leading edge of the model, i.e., the roof, at angles of attack of less than 40 degrees, the flow became turbulent after reattachment. This resulted in a higher heat transfer than previously reported in the literature. At higher angles of attack, the flow was not separated at the leading edge and remained laminar. The heat transfer coefficient for higher angles of attack, i.e., α > 40 deg, was found to be approximately independent of the angle of attack and in good agreement with the previously published results.

Transient Free Convection About Vertical Plates and Circular Cylinders

1964 ◽  
Vol 86 (4) ◽  
pp. 490-500 ◽  
Author(s):  
R. J. Goldstein ◽  
D. G. Briggs
Keyword(s):  
Heat Transfer ◽  
Free Convection ◽  
Transfer Problem ◽  
Convection Heat Transfer ◽  
Circular Cylinders ◽  
Flat Plates ◽  
One Dimensional ◽  
Free Convection Heat ◽  
Good Agreement ◽  
Quiescent Fluid

An analysis is made of the transient free-convection, heat-transfer problem from vertical flat plates and vertical circular cylinders to a surrounding initially quiescent fluid. The transient is initiated by a change in wall temperature of the plate or cylinder. A method of predicting the length of time for which a one-dimensional regime of velocity and heat transfer will exist is proposed and solutions are presented. Good agreement is found with the few existing data.

Unsteady Boundary Layers on a Flat Plate Disturbed by Periodic Wakes: Part II—Measurements of Unsteady Boundary Layers and Discussion

1996 ◽  
Vol 118 (2) ◽  
pp. 337-344 ◽  
Author(s):  
K. Funazaki
Keyword(s):  
Boundary Layer ◽  
Flat Plate ◽  
Boundary Layers ◽  
Time Domain ◽  
Indirect Effect ◽  
Transition Model ◽  
Hot Wire ◽  
Turbulent Spot ◽  
Boundary Layer Interaction ◽  
Unsteady Boundary Layers

As the second part of the study, detailed hot-wire anemometry measurements of wake-affected boundary layers on the flat plate are made. These measurements are organized in order, first, to check the standpoint of the modeling of the wake-induced transition proposed in Part I, and second, to observe wake–boundary layer interaction in detail from a viewpoint of direct and indirect effect of the wake passage upon turbulent spot generation within the boundary layer, as described by Walker (1993). The validity of the presumed state of the wake-affected boundary layer in the distance–time domain, which constitutes the basis of the transition model, is confirmed to great extent. However, it is also found that the criterion for the onset of the wake-induced transition adopted in Part I should be reconsidered. Some successful attempts are therefore made to specify the transition onset.

A Theory for Wake-Induced Transition

1990 ◽  
Vol 112 (2) ◽  
pp. 188-195 ◽  
Author(s):  
R. E. Mayle ◽  
K. Dullenkopf
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Turbulent Flow ◽  
Flat Plate ◽  
Free Stream ◽  
Plate Boundary ◽  
Transition Model ◽  
Model Comparisons ◽  
Turbulent Wakes ◽  
Flat Plate Boundary Layer

A theory for transition from laminar to turbulent flow as the result of unsteady, periodic passing of turbulent wakes in the free stream is developed using Emmons’ transition model. Comparisons made to flat plate boundary layer measurements and airfoil heat transfer measurements confirm the theory.

Reference Temperatures for Supercritical Laminar Free Convection on a Vertical Flat Plate

1981 ◽  
Vol 103 (4) ◽  
pp. 613-616 ◽  
Author(s):  
A. J. Ghajar ◽  
J. D. Parker
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Free Convection ◽  
Flat Plate ◽  
Reference Temperature ◽  
Variable Property ◽  
Temperature Method ◽  
Theoretical Results ◽  
Vertical Flat Plate ◽  
Good Agreement

A reference temperature method was developed by which heat transfer to fluids in the supercritical region under variable property conditions in laminar free convection on a vertical flat plate can be readily evaluated. Based on this method three generalized plots for Refrigerant-114, water, and carbon dioxide were developed. The results obtained with the reference temperature scheme showed good agreement with the existing experimental data and theoretical results for these three variable property fluids.

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