The project employs optical and video techniques to record pattern formation in classical fluids such as acetone and water. Thermal convection, flow, and imposed electric fields induce density fluctuations or patterns in non-equilibrium systems that can detected by optical means. These patterns can be irregular both in space and in time. The mathematical description of such irregularity is often described by deterministic macroscopic equations and is referred to as spatio- temporal chaos (STC). However, an additional stochastic term representing local microscopic fluctuations (thermal noise external to the deterministic equations) is also thought to be important in STC. The purpose of this project is to seek experimental evidence for the external noise in different fluids and in different geometries. The project involves strong collaboration between the principal investigator and theorists in the U.S. and in Germany. The results are of fundamental interest and are also of technological interest in the behavior of liquid crystals in electric fields, engineering fluid dynamics, and re lated fields. % % % The project employs optical and video techniques to observe and record pattern formation in classical fluids such as acetone and water. Thermal convection, flow, and imposed electric fields induce density fluctuations or patterns that can detected by optical means. These patterns are in some ways similar to patterns appearing in smoke plumes rising and moving by convection in front of a theater projection lens. The mathematical description of such phenomena is quite complex and careful experiments, as proposed by the principal investigator, are required to test extant probabilistic theories of pattern formation. The project involves strong collaboration between the principal investigator and theorists in the U.S. and in Germany. The results are of fundamental interest and are also of technological interest in the behavior of liquid crystals in electric fields, engineering fluid dynamics, and related fields.
