Pressure and velocity fluctuations in the atmospheric boundary layer

This paper presents an analysis of wind velocity and pressure data obtained in a rural environment with a view to identifying the vortex structures present within the flow and examining the relationship between pressure and dynamic pressure. The data is analysed using both conventional analysis and conditional sampling. A method examining the eigenvalues of a matrix formed by the addition of the square of the strain tensor and the square of the vorticity tensor is also investigated. This method illustrates that there are a number of vortex structures present in the flow. The work presented in this paper suggests that the extreme events occur as a result of the superposition of two independent mechanisms.

[1]  Jinhee Jeong,et al.  On the identification of a vortex , 1995, Journal of Fluid Mechanics.

[2]  J. A. Elliott Microscale pressure fluctuations measured within the lower atmospheric boundary layer , 1972, Journal of Fluid Mechanics.

[3]  Peter Richards,et al.  Anisotropic turbulence in the atmospheric surface layer , 1997 .

[4]  H. E. Fiedler,et al.  Coherent structures in turbulent flows , 1988 .

[5]  Fazle Hussain,et al.  Coherent structures near the wall in a turbulent channel flow , 1997, Journal of Fluid Mechanics.

[6]  C. Baker,et al.  Aspects of the use of proper orthogonal decomposition of surface pressure fields , 2000 .

[7]  Patrice Abry,et al.  Intermittency and coherent structures in a swirling flow: A wavelet analysis of joint pressure and velocity measurements , 1999 .

[8]  S. K. Robinson,et al.  Coherent Motions in the Turbulent Boundary Layer , 1991 .

[9]  M. Parlange,et al.  Spectral scaling of static pressure fluctuations in the atmospheric surface layer: The interaction between large and small scales , 1998 .

[10]  J. Finnigan,et al.  Coherent eddies and turbulence in vegetation canopies: The mixing-layer analogy , 1996 .

[11]  A. Hussain,et al.  Coherent structures and turbulence , 1986, Journal of Fluid Mechanics.

[12]  J. Kulkarni,et al.  A Study Of Coherent Structures In The Atmospheric Surface Layer Over Short And Tall Grass , 2001 .

[13]  F. Belin,et al.  Observation of Intense Filaments in Fully Developed Turbulence , 1996 .

[14]  Joseph T. C. Liu,et al.  Coherent Structures in Transitional and Turbulent Free Shear Flows , 1989 .

[15]  Christopher Baker,et al.  Unsteady wind loading on a wall , 2001 .

[16]  R. P. Hoxey,et al.  Short term unsteady wind loading on a low-rise building , 2003 .