Internal Lee Waves in Turbulent Two‐Layer Flow

Abstract

A mathematical model and laboratory experiments are described that deal with two‐layer flow over small‐scale bottom topography in relatively shallow, (partially) stratified estuaries. The mathematical model is based on Boussinesq‐type equations, which in an approximate way account for vertical accelerations, and assumes quasi‐steady flow. The analysis includes the effect of turbulent friction at bottom and sidewalls. In the experiments the positions of the interface, horizontal velocities, and turbulence intensities are measured. An increase in turbulence level downstream of the obstacle is observed, and a fair agreement with predicted lee‐wave amplitudes, wavelengths, and wave damping is obtained.