A Coupled Potential-Boundary Layer Calculation Method for Unsteady Flows Around Airfoils

1993 ◽  
pp. 129-143
Author(s):  
M. Kermarec ◽  
A. F. Decaix ◽  
P. Renon ◽  
D. Favier ◽  
C. Maresca
Keyword(s):  
Boundary Layer ◽  
Calculation Method ◽  
Unsteady Flows

A simple calculation method for estimating the flow velocity on the roof of a train running through a tunnel using an unsteady incompressible flow model

2019 ◽  
Vol 234 (7) ◽  
pp. 734-748
Author(s):  
Katsuhiro Kikuchi ◽  
Satoru Ozawa ◽  
Yuhei Noguchi ◽  
Shinya Mashimo ◽  
Takanobu Igawa
Keyword(s):  
Boundary Layer ◽  
Flow Velocity ◽  
Calculation Method ◽  
Model Experiment ◽  
Flow Model ◽  
Simple Calculation ◽  
Dimensional Model ◽  
One Dimensional ◽  
Calculation Results ◽  
Tunnel System

Predicting the aerodynamic phenomena in a train-tunnel system is important for increasing the speed of railway trains. Among these phenomena, many studies have focused on the effects of pressure; however, only a few studies have examined the effects of flow velocity. When designing train roof equipment such as a pantograph and an aerodynamic braking unit, it is necessary to estimate the flow velocity while considering the influence of the boundary layer developed on the train roof. Until now, numerical simulations using a one-dimensional model have been utilized to predict the flow velocity around a train traveling through a tunnel; however, the influence of the boundary layer cannot be taken into consideration in these simulations. For this purpose, the authors have previously proposed a simple calculation method based on a steady incompressible tunnel flow model that can take into account the influence of the boundary layer, but this method could not incorporate the unsteadiness of the flow velocity. Therefore, in this study, the authors extend the previous simple calculation method such that it can be used for an unsteady incompressible tunnel flow. The authors compare the calculation results obtained from the extended method with the results of a model experiment and a field test to confirm its effectiveness.

An Accurate Calculation Method for Two-dimensional Incompressible Laminar Boundary Layers, Including Cases with Regions of Sharp Pressure Gradient

1977 ◽  
Vol 28 (3) ◽  
pp. 149-162 ◽  
Author(s):  
N Curle
Keyword(s):  
Boundary Layer ◽  
Pressure Gradient ◽  
Calculation Method ◽  
Boundary Layer Separation ◽  
Pressure Gradients ◽  
Accurate Calculation ◽  
Boundary Layer Equations ◽  
Laminar Boundary Layers ◽  
Displacement Thickness ◽  
Type Boundary

SummaryThe paper develops and extends the calculation method of Stratford, for flows in which a Blasius type boundary layer reacts to a sharp unfavourable pressure gradient. Whereas even the more general of Stratford’s two formulae for predicting the position of boundary-layer separation is based primarily upon an interpolation between only three exact solutions of the boundary layer equations, the present proposals are based upon nine solutions covering a much wider range of conditions. Four of the solutions are for extremely sharp pressure gradients of the type studied by Stratford, and five are for more modest gradients. The method predicts the position of separation extremely accurately for each of these cases.The method may also be used to predict the detailed distributions of skin friction, displacement thickness and momentum thickness, and does so both simply and accurately.

Studies on boundary-layer separation in unsteady flows using an integral method

1984 ◽  
Vol 149 (-1) ◽  
pp. 477 ◽  
Author(s):  
Michinori Matsushita ◽  
Shigeru Murata ◽  
Teruaki Akamatsu
Keyword(s):  
Boundary Layer ◽  
Integral Method ◽  
Unsteady Flows ◽  
Boundary Layer Separation ◽  
Layer Separation

A hypersonic aeroheating calculation method based on inviscid outer edge of boundary layer parameters

2016 ◽  
Vol 129 ◽  
pp. 429-437
Author(s):  
ZhuXuan Meng ◽  
Hu Fan ◽  
Ke Peng ◽  
WeiHua Zhang ◽  
HuiXin Yang
Keyword(s):  
Boundary Layer ◽  
Calculation Method ◽  
Outer Edge

Approximate Calculations of the Incompressible Laminar Boundary Layer

1967 ◽  
Vol 18 (3) ◽  
pp. 259-272 ◽  
Author(s):  
M. R. Head ◽  
N. Hayasi
Keyword(s):  
Boundary Layer ◽  
Exact Solution ◽  
Approximate Method ◽  
Laminar Boundary Layer ◽  
Calculation Method ◽  
Close Agreement ◽  
Computer Solution ◽  
Three Solutions ◽  
Recent Calculation ◽  
Good Agreement

SummaryA recent calculation method proposed by Curle has been applied to the flow U=U0ξe-ξ for which a computer solution exists. An earlier approximate method due to Head, presented here in a simplified form, has been applied to the same problem. All three solutions are found to be in close agreement. A further problem, already examined by Curle, is treated by Head’s method. Again the results are in good agreement with each other and with an exact solution obtained subsequently.

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