Wind Tunnel Investigation of a Complex Canopy Shear Flow

2001 ◽  
Vol 28 (4) ◽  
pp. 12
Author(s):  
Ye. A. Gayev ◽  
Eric Savory ◽  
Norman Toy
Keyword(s):  
Wind Tunnel ◽  
Shear Flow

Further experiments in nearly homogeneous turbulent shear flow

1977 ◽  
Vol 81 (4) ◽  
pp. 657-687 ◽  
Author(s):  
V. G. Harris ◽  
J. A. H. Graham ◽  
S. Corrsin
Keyword(s):  
Wind Tunnel ◽  
Shear Flow ◽  
Energy Exchange ◽  
Turbulent Energy ◽  
Turbulent Shear ◽  
Asymptotic State ◽  
Turbulent Shear Flow ◽  
Tensor Structure ◽  
Mean Velocity ◽  
Exchange Hypothesis

The experiment of Champagne, Harris & Corrsin in generating and studying a nearly homogeneous turbulent shear flow has been extended to larger values of the dimensionless downstream time or strain by the use of a larger mean velocity gradient in the same wind tunnel. The system appears to reach an asymptotic state in which scales and turbulent energy grow monotonically. Two-point covariances and tensor structure of one-point ‘Reynolds stress’ and ‘pressure/strain-rate covariance’ agree with the earlier case. However, the linear intercomponent energy exchange hypothesis due to Rotta, very roughly confirmed by the earlier experiment, is contradicted by the present data.

scholarly journals Generation of Uniform Shear Flow in Wind Tunnel

1982 ◽  
Vol 1982 (14) ◽  
pp. 23-30 ◽  
Author(s):  
Syunsuke IKEDA ◽  
Masahiro TANAKA
Keyword(s):  
Wind Tunnel ◽  
Shear Flow ◽  
Uniform Shear ◽  
Uniform Shear Flow

The production of uniform shear flow in a wind tunnel

1957 ◽  
Vol 2 (06) ◽  
pp. 521 ◽  
Author(s):  
P. R. Owen ◽  
H. K. Zienkiewicz
Keyword(s):  
Wind Tunnel ◽  
Shear Flow ◽  
Uniform Shear ◽  
Uniform Shear Flow

scholarly journals Effects of Shear Layer Characteristics on Acoustic Propagation and Source Localization

2019 ◽  
Vol 37 (6) ◽  
pp. 1148-1157
Author(s):  
Lican Wang ◽  
Rongqian Chen ◽  
Yancheng You ◽  
Zhengwu Chen ◽  
Ruofan Qiu
Keyword(s):  
Wind Tunnel ◽  
Shear Flow ◽  
Shear Layer ◽  
Source Localization ◽  
Source Term ◽  
Acoustic Propagation ◽  
Linearized Euler Equations ◽  
Self Similar ◽  
The Mean ◽  
Beamforming Technique

The shear layer characteristics of an open-jet acoustic wind tunnel are of key importance on measurements of aeroacoustics. The effects of thickness, spreading angle and strength of shear layer on acoustic propagation and source localization are investigated through the mean/spreading shear layer with a self-similar velocity distribution. Based on the shear flow, the acoustic propagation is computed by the linearized Euler equations via a source term, and then source localization is obtained from beamforming technique combined with the theory of Amiet. Results show that the numerical method can precisely capture the refraction and reflection after sound traversing shear layer. The thickness, spreading angle and strength of the shear layer exerts little effects on the refracted region where sound wave nearly vertical incident, while mainly influence the corresponding up/downstream region in terms of phase change. Increment of thickness, spreading angle and strength of the shear layer increases the acoustic difference between the shear layer with and without thickness, and produces a larger error of source localization downstream of the actual position.

Experiments in nearly homogenous turbulent shear flow with a uniform mean temperature gradient. Part 1

1981 ◽  
Vol 104 ◽  
pp. 311-347 ◽  
Author(s):  
Stavros Tavoularis ◽  
Stanley Corrsin
Keyword(s):  
Wind Tunnel ◽  
Temperature Gradient ◽  
Shear Flow ◽  
Correlation Functions ◽  
Temperature Fluctuations ◽  
Turbulent Shear ◽  
Turbulent Shear Flow ◽  
Integral Scales ◽  
Probability Densities ◽  
Point Correlation

A reasonably uniform mean temperature gradient has been superimposed upon a nearly homogeneous turbulent shear flow in a wind tunnel. The overheat is small enough to have negligible effect on the turbulence. Away from the wind-tunnel entrance, the transverse statistical homogeneity is good and the temperature fluctuations and their integral scales grow monotonically like the corresponding velocity fluctuations (Harris, Graham & Corrsin 1977). Measurements of several moments, one- and two-point correlation functions, spectra, integral scales, microscales, probability densities, and joint probability densities of the turbulent velocities, temperature fluctuations, and temperature-velocity products are reported. The heat-transport characteristics are much like those of momentum transport, with the turbulent Prandtl number nearly 1. The temperature fluctuation is better correlated with the streamwise than the transverse velocity component, and the cross-component D12 of the turbulent diffusivity tensor has sign opposite to and about twice the magnitude of the diagonal component D22. Some resemblance of directional properties (relative magnitudes of correlation functions, integral scales, microscales) of the temperature with those of the streamwise velocity is also observed. Comparisons of the present data with measurements in the inner part of a heated boundary layer and a fully turbulent pipe flow (x2/d = 0·25) show comparable magnitudes of temperature-velocity correlation coefficients, turbulent Prandtl numbers and ratios of turbulent diffusivities, and show similar shapes of two-point correlation functions.

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