SUMMARYSpectra have been measured over a variety of types of complex terrain: on tops of hills and escarpments, Differences between spectra over many types of complex terrain, and over uniform terrain, can be When air moves over terrain with changed characteristics, then(1) for wavelengths very short relative to the fetch over the new terrain, the spectral densities are in equilibrium with the new terrain.(2) for wavelengths long compared to this fetch, spectral densities remain unchanged if the ground is horizontal, and decrease when the flow is uphill, for the longitudinal velocity component only. Since vertical-velocity spectra contain relatively less low wavenumber energy than horizontal-velocity over land downstream of a water surface, and over rolling terrain.explained by these hypotheses: spectra, energetic vertical-velocity fluctuations tend to be in equilibrium with local terrain.
It is shown that the ratio of standard deviation of lateral velocity to the friction velocity, o;/u,, and therefore wind direction fluctuations, are sensitive to mesoscale terrain properties. Under neutral conditions, a,/~, is almost 40% larger in rolling terrain than over a horizontal surface. In the lee of a low mountain, the fluctuations may be 2.5 times as strong as over horizontal terrain.In contrast, vertical velocity fluctuations are little influenced by mesoscale terrain features.
The typical infiltration load for a residential building has been found to range from onethird to one-half of the total space conditioning load. However, most infiltration measurements have been made on single-family houses. Inform~tion about the role of infiltration in the energy consumption of large buildings is limited. Furthermore, the prediction of infiltration rates in high-rise buildings is a complex problem. The forces that drive this flow result from the superposition of wind pressure on the faces of the building and the stack effect across the height of the building. Infiltration. models have shown the latter effect to be significan t in single-family residences, particularly in colder climates and, consequently, the stack effect is even greater in high-rise buildings. For this work, we performed traCer gas and fan pressurization measurements on a 30 m tall University of California dormitory in order .to determine the importance of both wind and stack effect upon infiltration. Measured pressure and tracer gas distributions were compared with those from a predictive infiltration computer model for high-rise buildings. To study the influence of the air flow pattern around the building, this model uses various wind velocity profiles characteristic of urban areas and different sets of surface pressure coefficients derived from wind tunnel experiments. Keywords: air-infiltration 'multi-cell' calculation model, thermal buoyancy and wind effect, Ian pressurization, leakage area, tracer gas measurements, wind pressure data, and air infiltration calculation.-1- .. . . 8.temperature (oe)
Spectra have been measured over a variety of types of complex terrain: on tops of hills and escarpments, Differences between spectra over many types of complex terrain, and over uniform terrain, can be When air moves over terrain with changed characteristics, then(1) for wavelengths very short relative to the fetch over the new terrain, the spectral densities are in equilibrium with the new terrain.(2) for wavelengths long compared to this fetch, spectral densities remain unchanged if the ground is horizontal, and decrease when the flow is uphill, for the longitudinal velocity component only. Since vertical-velocity spectra contain relatively less low wavenumber energy than horizontal-velocity over land downstream of a water surface, and over rolling terrain. explained by these hypotheses: spectra, energetic vertical-velocity fluctuations tend to be in equilibrium with local terrain.
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