Integral Skin Friction Prediction for Turbulent Separated Flows

1986 ◽  
Vol 108 (4) ◽  
pp. 476-482 ◽  
Author(s):  
D. K. Das ◽  
F. M. White
Keyword(s):  
Skin Friction ◽  
Integral Method ◽  
Separated Flows ◽  
Two Dimensional ◽  
Governing Equations ◽  
Variable Theory ◽  
Gradient Parameter ◽  
Logarithmic Law ◽  
Friction Prediction ◽  
Wake Parameter

An integral method is presented for computing incompressible two-dimensional turbulent skin friction for separated flows based on the inner-variable theory. Using a velocity profile in the form of the logarithmic law and wake, continuity and momentum equations are integrated across the boundary layer in terms of inner-variables u+ and y+. With the aid of correlations relating the wake parameter to the pressure gradient parameter, derived from experimental results of several near-separating and separated flows, the governing equations are reduced to a single differential equation in skin friction. Predictions by the theory for several separated flows show satisfactory agreement with experimental data.

Hydrodynamics in Tubes Perturbed by Curvilinear Obstructions

1984 ◽  
Vol 106 (3) ◽  
pp. 262-269 ◽  
Author(s):  
A. K. Rastogi
Keyword(s):  
Fluid Flow ◽  
Turbulent Flows ◽  
Separated Flows ◽  
Curvilinear Coordinates ◽  
Two Dimensional ◽  
Governing Equations ◽  
Curved Boundaries ◽  
Numerical Grid ◽  
Orthogonal Curvilinear Coordinates ◽  
Laminar And Turbulent Flows

A calculation procedure for two-dimensional separated flows over curved boundaries, e.g., flow in constricted tubes, is described. The method is based on the numerical solution with finite differences of the governing equations in orthogonal curvilinear coordinates. A body fitted curvilinear orthogonal numerical grid is generated first which is then employed for the solution of partial differential equations governing fluid flow. Results of calculations are presented for laminar and turbulent flows in constricted tubes. For turbulent flow calculations the k-ε turbulence model has been employed. Comparison between computed and measured values of flow quantities is also presented and is discussed in some detail. Although the present paper deals only with constricted pipes, the method developed is general and can be used without difficulty for two-dimensional flows over other curved boundaries.

Evaluation of the momentum integral method to determine the wall skin friction in separated flows

2020 ◽  
Vol 61 (12) ◽  
Author(s):  
Meagan E. Wengrove ◽  
Alireza Ebadi ◽  
Christopher M. White ◽  
Diane L. Foster
Keyword(s):  
Skin Friction ◽  
Integral Method ◽  
Separated Flows ◽  
Momentum Integral

scholarly journals Assessing IDDES-Based Wall-Modeled Large-Eddy Simulation (WMLES) for Separated Flows with Heat Transfer

Fluids ◽  
2021 ◽  
Vol 6 (7) ◽  
pp. 246
Author(s):  
Rozie Zangeneh
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Large Eddy Simulation ◽  
Skin Friction ◽  
Heat Fluxes ◽  
Separated Flows ◽  
Detached Eddy Simulation ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Isothermal Wall

The Wall-modeled Large-eddy Simulation (WMLES) methods are commonly accompanied with an underprediction of the skin friction and a deviation of the velocity profile. The widely-used Improved Delayed Detached Eddy Simulation (IDDES) method is suggested to improve the prediction of the mean skin friction when it acts as WMLES, as claimed by the original authors. However, the model tested only on flow configurations with no heat transfer. This study takes a systematic approach to assess the performance of the IDDES model for separated flows with heat transfer. Separated flows on an isothermal wall and walls with mild and intense heat fluxes are considered. For the case of the wall with heat flux, the skin friction and Stanton number are underpredicted by the IDDES model however, the underprediction is less significant for the isothermal wall case. The simulations of the cases with intense wall heat transfer reveal an interesting dependence on the heat flux level supplied; as the heat flux increases, the IDDES model declines to predict the accurate skin friction.

scholarly journals Influence of a Standing Wave Flow-Field on the Dynamics of a Spray Diffusion Flame

Fluids ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 27
Author(s):  
J. Barry Greenberg ◽  
David Katoshevski
Keyword(s):  
Liquid Phase ◽  
Flow Field ◽  
Standing Wave ◽  
Diffusion Flame ◽  
Stokes Number ◽  
Flame Height ◽  
Wave Flow ◽  
Two Dimensional ◽  
Governing Equations ◽  
First Time

A theoretical investigation of the influence of a standing wave flow-field on the dynamics of a laminar two-dimensional spray diffusion flame is presented for the first time. The mathematical analysis permits mild slip between the droplets and their host surroundings. For the liquid phase, the use of a small Stokes number as the perturbation parameater enables a solution of the governing equations to be developed. Influence of the standing wave flow-field on droplet grouping is described by a specially constructed modification of the vaporization Damkohler number. Instantaneous flame front shapes are found via a solution for the usual Schwab–Zeldovitch parameter. Numerical results obtained from the analytical solution uncover the strong bearing that droplet grouping, induced by the standing wave flow-field, can have on flame height, shape, and type (over- or under-ventilated) and on the existence of multiple flame fronts.

Bifurcation analysis of two-dimensional laminar flow through sudden expansion channel

2022 ◽  
Vol 13 (1) ◽  
pp. 0-0
Keyword(s):  
Laminar Flow ◽  
Expansion Ratio ◽  
Sudden Expansion ◽  
Two Dimensional ◽  
Governing Equations ◽  
Bifurcation Phenomena ◽  
Different Types ◽  
Fluent Software ◽  
Flow Through ◽  
Volume Method

In this work, bifurcation characteristics of unsteady, viscous, Newtonian laminar flow in two-dimensional sudden expansion and sudden contraction-expansion channels have been studied for different values of expansion ratio. The governing equations have been solved using finite volume method and FLUENT software has been employed to visualize the simulation results. Three different mesh studies have been performed to calculate critical Reynolds number (Recr) for different types of bifurcation phenomena. It is found that Recr decreases with the increase in expansion ratio (ER).

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