Experimental investigation of local scour around circular bridge piers under steady state flow conditions

Author(s):  
A O Aksoy ◽  
O Y Eski
Author(s):  
Ken-ichi Funazaki ◽  
Nozomi Tanaka ◽  
Takahiro Shiba ◽  
Haruyuki Tanimitsu ◽  
Masaaki Hamabe

The study the present authors have been working on is to develop a new method to increase aerodynamic loading of low-pressure turbine airfoils for modern aeroengines to a great extent, which is to achieve drastic reduction of their airfoil counts. For this purpose, this study proposes two-dimensional contouring of the airfoil suction surface as a device to suppress the separation bubble that causes large aerodynamic loss, especially at low Reynolds number condition. The main objective of this paper is to show how and to what extent the surface contouring without any other disturbances affects the suction surface boundary layer accompanying separation bubble. For comparison, rather conventional tripping wire technique is also employed as “local 2D surface contouring” to generate flow disturbances in order to suppress the separation bubble. All measurements are carried out under steady-state flow conditions with low freestream turbulence. It turns out from the detailed experiments and LES analysis that the newly proposed two-dimensional contouring of the airfoil surface can effectively suppress the separation bubble, resulting in significant improvement of cascade aerodynamic performance.


2011 ◽  
Vol 120 (6) ◽  
pp. 944-959 ◽  
Author(s):  
Tetsuya KOGURE ◽  
Keigo KITAMURA ◽  
Tatsuya YAMADA ◽  
Osamu NISHIZAWA ◽  
Ziqiu XUE

2018 ◽  
Vol 45 (1) ◽  
pp. 83-94
Author(s):  
Jela Burazer

Energy separation is a spontaneous energy redistribution within a fluid flow. As a consequence, there are places with higher and lower values of total temperature in the fluid flow. It is characteristic for many flow geometries. This paper deals with the energy separation in a cylinder wake. Two flow conditions are being considered-transient and steady-state flow in the wake. Two different solvers from the open source package OpenFOAM are used in order to capture the phenomenon of energy separation. One of these solvers is modified for the purpose of calculation in a particular case of the vortex street flow. The energy equation based on the internal energy present in this solver is replaced by the energy equation written in the form of a total enthalpy. The other solver has been previously tested in the vortex tube flow, and can also capture the energy separation in the steady-state wake flow of the cylinder. In both cylinder wake flow conditions, a two-dimensional computational domain is used. Standard ?? ? ?? model is used for computations. It is proved that OpenFOAM is capable of capturing the energy separation phenomenon in a proper way in both of the wake flow cases. Good agreement between the experimental results and the ones from computations is obtained in the case of steady-state flow in the wake. Previous research findings are also confirmed in the case of vortex street flow.


2002 ◽  
Vol 13 (05) ◽  
pp. 675-687 ◽  
Author(s):  
MASSIMO BERNASCHI ◽  
SAURO SUCCI ◽  
HUDONG CHEN ◽  
RAOYANG ZHANG

An accelerated version of the lattice Boltzmann equation aimed at fast attainment of steady-state flow conditions is presented. Significant computational savings as compared to the standard explicit LBE scheme are obtained for cavity flows in two dimensions.


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