Characteristics Of Wind Profiles Research Articles

An aerodynamic formula to compute evaporation from open water surfaces

A formula to compute evaporation from open water surfaces is derived using wind profile characteristics. The mass transfer coefficient is given as a function of the shape and size of the water body in addition to the turbulent boundary layer parameters. The formula has been applied successfully to lakes and reservoirs of areas ranging from a fraction of an acre to thousands of acres. It is also given in a simplified form for application to cases where the wind profile measurements are not made.

Wind structure in the atmospheric boundary layer

The semi-empirical laws for the variation of mean wind speed with height and for the statistical properties of the turbulent fluctuations are briefly outlined. Similarity considerations provide some useful ordering of the mean wind profile characteristics in relation to surface roughness and thermal stratification. Appreciable uncertainties prevail, however, especially as a consequence of the effect of thermal stratification and of variable terrain roughness. Some generalization on similarity grounds can also be made regarding the fluctuations of horizontal wind speed as a function of roughness and stability, but there are wide variations of spectral density and scale which are not immediately explicable and which at present preclude anything more than a relatively coarse specification of the spectrum. Features which are of special relevance to architectural aerodynamics and which are discussed briefly are: ( a ) the difficulty of generalizing about the wind profile and turbulence above an urban complex; ( b ) the requirement for estimating the magnitudes of extreme gusts as a function of mean wind speed, averaging time and height; ( c ) the problem of generalizing about flow properties below roof level; ( d ) the effect of urban airflow on the travel and dispersion of pollutants