Accession Number : AD0676081

Title :   UNDULANCE AND TURBULENCE IN STABLY STRATIFIED MEDIA,

Corporate Author : BOEING SCIENTIFIC RESEARCH LABS SEATTLE WASH FLIGHT SCIENCES LAB

Personal Author(s) : Pao,Yih-Ho

Report Date : AUG 1968

Pagination or Media Count : 30

Abstract : The origin and the structure of undulance and turbulence in stably stratified media are investigated through theoretical reasoning and laboratory experiments. The mechanisms for generating turbulence in stably stratified media are linked with the mechanisms for generating vorticity - shear and stratification. The dual role of stable stratification -- the capability for generating and attenuating turbulence -- is pointed out. The turbulence induced by stable stratification is evidenced in two experimental results: (1) turbulent rotors in the lee of a barrier in a stably stratified fluid, and (2) the breaking of traveling internal waves on a sloping surface. The ability of stable stratification to generate turbulence is also indicated from an exact solution for an inviscid stably stratified flow past a barrier. The structure of undulance and turbulence in stably stratified media is investigated in a stratified salt water towing tank, with schlieren photographs, quartz-coated hot-film probes, and single electrode conductivity probes. The schlieren photographs show clearly the collapse of a turbulent wake and the attenuation of turbulence by stable stratification. Auto-correlations and -spectra for the streamwise turbulent velocity field and for the turbulent concentration field are obtained. From the measured correlations and spectra, the combined wave-turbulence behavior is clearly shown, and the turbulence is strongly anisotropic. (Author)

Descriptors :   (*ATMOSPHERIC MOTION, *CLEAR AIR TURBULENCE), TROPOSPHERE, ATMOSPHERE MODELS, STRATOSPHERE, VORTICES, STABILITY, ATTENUATION, FLOW VISUALIZATION

Subject Categories : Aerodynamics
      Atmospheric Physics
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE