Drag Force Caused by Gravity Waves over a Mountain Barrier

Abstract

Internal gravity waves caused in the fluid with vertical density gradient passing over a solitary barrier are studied. The patterns of gravity waves numerically computed for the cases of the internal Froude number of 0. 25, 0.20 and 0.125 are compared well with the experimental results obtained by R. Long (1955). On the other hand, the drag coefficient CD is derived analytically from a linearized equation and is given by CD∞1/Fi(1-3/4H2/b2Fi2), where Fi is the Froude number, H the depth of channel and b the characteristic scale of height of the mountain barrier. This formula is checked by the numerical computation with a complete form of non-linear equation.