EXPERIMENTAL GENERATION OF STRATIFIED SHEAR FLOW BY WAVE MOMENTUM TRANSPORT

THIS PROPOSAL IS A JOINT EXPERIMENTAL, THEORTICAL, AND NUMERICAL STUDY OF GRAVITY WAVE - CRITICAL LAYER INTERACTIONS. THESE INTERACTIONS ARE IMPORTANT IN UNDERSTANDING ATMOSPHERIC DYNAMICS BECAUSE OF STRESS DIVERGENCE AND MIXING THAT OCCUR AS A GRAVITY WAVE APPROACHES ITS CRITICAL LEVEL. THE OBJECTIVES OF PHASE I ARE TO GENERATE STEADY-STATE, STRATIFIED SHEAR FLOWS IN THE LABROATORY BY THE WAVE MOMENTUM TRANSPORT TECHNI QUE, AND TO MEASURE AND CHARACTRIZE THE RESULTING FLOWS. WE WILL GENERATE THESE SHEAR FLOWS BY ALLOWING A GRAVITY WAVE TO PROPAGATE INTO A STRATIFIED FLUID, THEREBY TRANSPORTING MOMENTUM FROM THE BOUNDARY AT WHICH THE WAVE IS FORCED TO THE INTERIOR FLUID WHERE THE WAVE IS DISSIPATED. THIS TECHNIQUE IS MOTIVATED BY THE GRAVITY WAVE EXPERIMENT OF PLUMB AND MCEWAN (1978). IN PHASE 2, WE WILL PROPAGATE ADDITIONAL GRAVITY WAVES INTO THE STRATIFIED SHEAR FLOW TO STUDY CRITICAL LAYER INTERACTIONS. THE MAJORITY OF THE PHASE I EFFORT IS TO CONSTRUCT AN EXPERIMENTAL FACILITY TO DETERMINE THE CHARACTERISTICS OF THE SHEAR FLOWS GENERATED BY THE WAVE MOMENTUM TRANSPORT TECHNIQUE. WE WILL USE THEORETICAL PREDICTIONS TO HELP US DESIGN THIS FACILITY. EXPERI MENTS WILL BE PERFORMED. AND THE MEASURED RESULTS WILL BE COMPARED TO BOTH THEORETICAL AND NUMERICAL PREDICTIONS.