عنوان مقاله [English]
Series of experiments is carried out to investigate the influence of a mountain on air flows around and over it. Experiments were concentrated on the role of orography in the adjustment process. Based on the results of experiments, we find that: (1) the final equilibrium state of the atmosphere is not geotropically balanced. The height of mountain influences the adjustment period; higher mountains make the adjustment period longer. (II) Fronts are not observed during geotropic adjustment, unlike what was suggested before. Although frontal features appear on the maps, their length scales are shorter than those of the atmospheric fronts. (III) The ratios of kinetic energy to the potential energy released during adjustment are smaller and larger than those predicted by the theory when, kinetic energy is computed from respectively geos trophic and actual winds. (IV) For small Froude numbers, the relation between mountain drag and Froude number is more complicated than what has already been suggested. (V) In the nonlinear regime studied here, splitting of flow and vertically propagating internal gravity waves are found as other major mechanisms for drag development in addition to the three possibilities suggested by Smith for linear regimes.