In this paper it was numerically simulated an air streamperpendiculary incident upon a valley in order to determine the influence of the Froude and the Rossby numbers in the pattern of the flow. The main of this study is to search under what range of the these parameters the air stream will be channeled in the vally. Theoretical considerations shows that the chenneling occur if the values of these numbers are limited in one region in the space defined by these parameters
