Under an SGER grant (Small Grant for Exploratory Research) a test for local isotropy of turbulence will be carried out by an NSF grantee at a large Reynolds number windtunnel at the NASA Ames Research Laboratory. The experiment will use special miniature multielement hot-wire probes, and the test for isotropy will be based on velocity gradient data. The experiment will help settle the question of how valid is the commonly held assumption of universality at the fine scales of turbulence at high Reynolds numbers, and the range of validity of this concept. Th concept forms the basis of present models of turbulent flow in various engineering systems, and improvement in such predictive models requires clarification of this basis.
