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The effect of wind shear on a puff
Author(s) -
Richards J. M.
Publication year - 1970
Publication title -
quarterly journal of the royal meteorological society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.744
H-Index - 143
eISSN - 1477-870X
pISSN - 0035-9009
DOI - 10.1002/qj.49709641011
Subject(s) - shearing (physics) , mechanics , physics , constant (computer programming) , momentum (technical analysis) , convection , shear (geology) , thermal wind , thermal , classical mechanics , wind shear , meteorology , wind speed , geology , thermodynamics , petrology , finance , computer science , economics , programming language
This paper corrects Hall's work in the light of more complete experiments which have established that a thermal is merely a special case of a buoyant puff. The general theory, presented here, applies to any isolated buoyant or non‐buoyant puff in shearing surroundings of uniform potential density. This theory is then applied to the case of constant mass deficit and constant wind shear, and solutions are obtained in the form of algebraic equations and simple definite integrals. When these solutions are evaluated numerically, using experimentally determined constants, it is found that the ratio of the coefficients of vertical transport of momentum and heat attributable to the puff lies in the range 0.27 σ to 0.7 σ approximately, where σ is the (small) proportion of the area of the horizontal plane through any height which is occupied by puffs. Also, realistic variation of the angle of spread of puffs is found to produce a very considerable effect on the depth of the convective layer. Only narrow puffs rise far.