Extreme Wind Data and Building Design

Abstract

for the balances of a unit mass element. The relevant processes are heating and cooling, vertical motion, friction, motion up or down a pressure gradient, and the total pressure work.What does the heating Q correspond to in the atmosphere? As noted by Panofsky (1978 (c)), the major agencies of heating are radiative flux convergence, and latent heat release in condensation of water vapour; the reverse processes are agencies of cooling. Frictional dissipation (see Fig. 4), whereby bulk flow KE is 'degraded' into IE by molecular viscosity, contributes only to the heating. Molecular conduction can contribute heating or cooling, but is generally unimportant except very close to material surfaces. All these processes occur on the molecular scale and thus tally with the usual thermodynamic picture of heating. Frequently, however, Q is extended to include the convergences or divergences of fluxes carried by eddy motion occurring on a smaller space scale than that of the 'element' of air which is under consideration.Our survey of the energy balances for a single fluid element is now complete. In Part I1 we shall consider the energy balances for the entire volume of a fluid systemthe balances formed by adding together the contributions of every fluid element in the system. REFERENCES ATKINSON, B. W. PANOYSKY, H. A.