In a discussion of wind fluctuations it is suggested that the structure of winds below 150 M is largely determined by the large-scale pressure gradient and the characteristics of turbulence. Two main forms of atmospheric turbulence are described as mechanical turbulence, driven by the vertical shear and the wind; and heat convection, generally driven by heating from below. The author considers that in strong winds, mechanical turbulence is frequently far stronger than heat convection, and that the latter can be neglected. This review of the subject is therefore concerned with wind properties under conditions of dominant mechanical turbulence, but the question of whether or not heat convection can be neglected is also discussed by reference to the richardson number. The review discusses the distribution of mean wind over homogeneous terrain in strong winds; the effect of stability on wind profiles by reference to the monin-obukhov theory; the effect of terrain change on wind speed, in that when air moves from rough to smooth terrain the surface stress immediately drops so that just above the ground the air accelerates; wind variability; and cross spectra of wind speed as described by cospectrum and quadrature spectrum or statistics derived from them. /TRRL/

  • Corporate Authors:

    Multi-Science Publishing Company, Limited

    The Old Mill, Dorset Place
    London E15 1DJ,   England 
  • Authors:
    • Panofsky, H A
  • Publication Date: 1977

Media Info

  • Features: Figures; References; Tables;
  • Pagination: p. 91-103
  • Serial:
    • Wind Engineering
    • Volume: 1
    • Issue Number: 2
    • Publisher: Multi-Science Publishing Company, Limited

Subject/Index Terms

Filing Info

  • Accession Number: 00179191
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: ITRD, TRIS
  • Created Date: Sep 27 1978 12:00AM