Statistical Characterization of High Reynolds Number Boundary Layer Turbulence Subjected to an Imposed Length Scale
Abstract
Scale separation at high Reynolds number (Re) suggests that intermediate scale dynamics are increasingly important. Given this, an experimental study was conducted to determine effects of an imposed length scale on high Re boundary layer turbulence. The experiment was performed in the near-neutrally stable (thermal) atmospheric boundary layer that flows over the salt playa of western Utah. A hemisphere of diameter 15.2cm, located 1m from the surface, and placed with its apex facing upstream was used to generate the imposed scale. A near-neutrally buoyant tracer was released from a point source (no imposed scale) and from around the hemisphere surface. Spatially and temporally resolved measurements were made with a unique scalar transport probe [Metzger, M. and Klewicki, J. Meas. Sci. Tech. 14 (2003), 1437], having a 6×4×4.8 mm^3 measurement volume. Statistical moments, length and time scales, spectra, and terms in the transport equations for the axial stress and scalar variance were acquired at two downstream locations. Results will be discussed relative to the influence of the imposed scale on local turbulence structure and the relaxation of the disturbed flow with downstream evolution.
- Publication:
-
APS Division of Fluid Dynamics Meeting Abstracts
- Pub Date:
- November 2003
- Bibcode:
- 2003APS..DFD.AA006A