Unsteady Boundary Layers Over Rotating Blades

Universal Functions ◽

Rotating Blades ◽

Flow And Heat Transfer ◽

Temperature Boundary ◽

Dimensional Boundary

Rotating blades provide some of the most challenging problems of fluid mechanics. The presence of secondary effects in the boundary layers over rotating blades results in the flow and heat transfer characteristics that are different from the classical two-dimensional boundary layer theory. In this paper, the unsteady velocity and thermal boundary layers have been solved for constant temperature boundary condition. By the use of small crossflow approximation, a perturbation analysis is developed to predict heat transfer characteristics. Numerical results for the universal functions proportional to primary flow and crossflow are presented. For the thermal problem, universal functions are presented for Pr = 0.70 and 1.0. Expressions for the skin friction coefficient as well as the Nusselt number have been derived.

STUDY OF EFFECT OF MOLECULAR PRANDTL NUMBER, TRANSPIRATION AND LONGITUDINAL PRESSURE GRADIENT ON FLOW AND HEAT TRANSFER CHARACTERISTICS IN BOUNDARY LAYERS

Computational Thermal Sciences An International Journal ◽

10.1615/computthermalscien.2018024497 ◽

2019 ◽

Vol 11 (1-2) ◽

pp. 41-49 ◽

Cited By ~ 2

Author(s):

Alexander I. Leontiev ◽

Valerii G. Lushchik ◽

Mariia S. Makarova

Keyword(s):

Heat Transfer ◽

Prandtl Number ◽

Pressure Gradient ◽

Boundary Layers ◽

Longitudinal Pressure Gradient ◽

Flow and Heat Transfer Over a Stretched Microsurface

Journal of Heat Transfer ◽

10.1115/1.3090811 ◽

2009 ◽

Vol 131 (6) ◽

Cited By ~ 15

Author(s):

Suhil Kiwan ◽

M. A. Al-Nimr

Keyword(s):

Heat Transfer ◽

Friction Coefficient ◽

Flat Plate ◽

Skin Friction ◽

Convection Heat Transfer ◽

Slip Parameter ◽

The convection heat transfer induced by a stretching flat plate has been studied. Similarity conditions are obtained for the boundary layer equations for a flat plate subjected to a power law temperature and velocity variations. It is found that a similarity solution exists only for a linearly stretching plate and only when the plate is isothermal. The analysis shows that three parameters control the flow and heat transfer characteristics of the problem. These parameters are the velocity slip parameter K1, the temperature slip parameter K2, and the Prandtl number. The effect of these parameters on the flow and heat transfer of the problem has been studied and presented. It is found that the slip velocity parameter affect both the flow and heat transfer characteristics of the problem. It is found that the skin friction coefficient decreases with increasing K1 and most of the changes in the skin friction takes place in the range 0<K1<1. A correlation between the skin friction coefficient and K1 and Rex has been found and presented. It is found that cf=23Rex−0.5(K1+0.64)−0.884 for 0<K1<10 with an error of ±0.8%. Other correlations between Nu and K1 and K2 has been found and presented in Eq. 28.

Flow and heat transfer characteristics of the boundary layers over a stretching surface with a uniform-shear free stream

International Journal of Heat and Mass Transfer ◽

10.1016/j.ijheatmasstransfer.2007.11.013 ◽

2008 ◽

Vol 51 (9-10) ◽

pp. 2199-2213 ◽

Cited By ~ 31

Author(s):

Tiegang Fang

Keyword(s):

Heat Transfer ◽

Boundary Layers ◽

Free Stream ◽

Stretching Surface ◽

Uniform Shear ◽

Flow and Heat Transfer Past a Stretching/Shrinking Sheet Using Modified Buongiorno Nanoliquid Model

Mathematics ◽

10.3390/math9233047 ◽

2021 ◽

Vol 9 (23) ◽

pp. 3047

Author(s):

Natalia C. Roşca ◽

Alin V. Roşca ◽

Emad H. Aly ◽

Ioan Pop

Keyword(s):

Heat Transfer ◽

Shrinking Sheet ◽

Hybrid Nanofluid ◽

Flow And Heat Transfer ◽

Hybrid Nanofluids ◽

Layer Flow ◽

Shrinking Surface

This paper studies the boundary layer flow and heat transfer characteristics past a permeable isothermal stretching/shrinking surface using both nanofluid and hybrid nanofluid flows (called modified Buongiorno nonliquid model). Using appropriate similarity variables, the PDEs are transformed into ODEs to be solved numerically using the function bvp4c from MATLAB. It was found that the solutions of the resulting system have two branches, upper and lower branch solutions, in a certain range of the suction, stretching/shrinking and hybrid nanofluids parameters. Both the analytic and numerical results are obtained for the skin friction coefficient, local Nusselt number, and velocity and temperature distributions, for several values of the governing parameters. It results in the governing parameters considerably affecting the flow and heat transfer characteristics.

Turbulent flow and heat transfer characteristics in U-tubes: A numerical study

Thermal Science ◽

10.2298/tsci0904175a ◽

2009 ◽

Vol 13 (4) ◽

pp. 175-181 ◽

Cited By ~ 1

Author(s):

Khalid Alammar

Keyword(s):

Heat Transfer ◽

Nusselt Number ◽

Friction Coefficient ◽

Turbulent Flow ◽

Skin Friction ◽

Local Skin ◽

Using the standard k-e model, 3-dimensional turbulent flow and heat transfer characteristics in U-tubes are investigated. Uncertainty is approximated using experimental correlations and grid independence study. Increasing the Dean number is shown to intensify a secondary flow within the curved section. The overall Nusselt number for the tube is found to decrease substantially relative to straight tubes, while the overall skin friction coefficient remains practically unaffected. Local skin friction coefficient, Nusselt number, and wall temperature along the tube wall are presented.