Fluid Dynamics of Flow over Hills/Mountains—Insights Obtained through Physical Modeling

Abstract

Physical modeling studies of atmospheric flow over hills and mountains span 60 years of research in more than seven countries. Early work in the 1920s led to evaluation of air currents around the Rock of Gibraltar for airfield safety. Water channel work by Long in the 1950s examined lee-wave development over the Sierra Nevada of California. During the 1970s and 1980s laboratory measurements examined speedup over idealized two- and three-dimensional hills and escarpments for wind-power climatology purposes. Since the mid-1960s many fluid-model tests have examined transport and dispersion of pollutants over complex terrain. Considered together there is a wealth of information about the influence of hills and mountains on streamline patterns, speedup, turbulence, and separation under many topographic and atmospheric conditions. This chapter will consider the advantages and limitations of physical modeling, review the principle conclusions drawn through physical modeling, and suggest experiments that might result in a better understanding of the flow processes over complex terrain.