Accession Number : ADA299567

Title :   Studies of the Nonlinear Dynamics of Fluid Systems.

Descriptive Note : Final rept.,

Corporate Author : OHIO STATE UNIV COLUMBUS DEPT OF PHYSICS

Personal Author(s) : Andereck, C. D.

PDF Url : ADA299567

Report Date : FEB 1995

Pagination or Media Count : 122

Abstract : Under ONR support we carried out an experimental study of the generalized hydrodynamic behavior of cellular patterns far from onset. We showed the basic qualitative effectiveness of the phase dynamics approach in modeling this behavior for both ordered and turbulent flows in the Taylor-Couette system. Although the experiments involved a specific system, the phase equations that describe them are determined by the pattern symmetries, so the results should generalize to other systems. In addition we performed a series of experiments on flows in the Taylor-Dean system, the flow between independently rotating concentric cylinders with a partially filled gap. By adjusting the rotation speeds of the two cylinders it is possible to tune the velocity profile across the gap over a wide range, and hence produce a large variety of flow patterns. We studied in detail several novel patterns and their evolution upon increasing the relevant control parameter. Finally, in a different area entirely, we studied two distinct liquid crystal systems. The first was a liquid crystal layer subjected to a noisy control parameter, which resulted in a state diagram in which the statistical probability density characteristics served as the distinguishing feature of the different states. The second was a study of phase winding in a thin layer of a liquid crystal subjected to rotationally induced shear. The outcome of this project is a better understanding of highly nonequilibrium ordered and turbulent patterns in both simple and complex fluid systems, and of the ability of phase dynamics to model long-wavelength low-frequency behaviors in some cases.

Descriptors :   *TURBULENT FLOW, *FLOW FIELDS, *NONLINEAR SYSTEMS, *NONEQUILIBRIUM FLOW, MATHEMATICAL MODELS, SPATIAL DISTRIBUTION, HYDRODYNAMIC CHARACTERISTICS, TIME DEPENDENCE, PHASE TRANSFORMATIONS, CHAOS, TURBULENCE, PHASE STUDIES, VORTICES, COMPUTATIONAL FLUID DYNAMICS, PROBABILITY DENSITY FUNCTIONS, LIQUID CRYSTALS, MATHEMATICAL PREDICTION, CYLINDRICAL BODIES, APPROXIMATION(MATHEMATICS), DIFFUSION, FLOW NOISE, LONG WAVELENGTHS, NAVIER STOKES EQUATIONS, BIFURCATION(MATHEMATICS), INSTABILITY, LOW FREQUENCY, TWO PHASE FLOW, AXIAL FLOW, COUETTE FLOW, SECONDARY FLOW.

Subject Categories : Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE