THE EFFECT OF HIGH INTENSITY TURBULENCE ON THE AERODYNAMICS OF A RIGID CIRCULAR CYLINDER AT SUBCRITICAL REYNOLDS NUMBER.
Abstract
The interaction of high intensity turbulence with the flow past a rigid circular cylinder was studied experimentally at subcritical Reynolds numbers. Grids were used to produce homogeneous turbulence fields with longitudinal scales ranging from 0.36D to 4.40D, and with longitudinal intensities greater than 10%. Power and cross-spectra of the turbulence components (the 'system input') were measured in order to carefully define the turbulence characterists. In particular, lateral coherences of the longitudinal component were found to collapse well when plotted versus zeta/lambda (lateral separation/wavelength) as suggested by Davenport. A model with which measurement of arbitrary two-point pressure correlations could be made was used in the response experiments. Subsequent integrations yielded the spectral properties of the unsteady drag and lift. Measurement of mean drag and Strouhal frequency indicate that to some extent even severe large-scale turbulence can be considered equivalent to an increase in the effective Reynolds Number. Vortex shedding is not disrupted drastically by severe turbulence, but is affected more by that at low frequency than at high. The unsteady lift response is still dominated by the vortex shedding, whereas the unsteady drag is primarily a response to turbulence. The cross-spectra of the drag collapse well when plotted versus zeta/lambda, and were used, for one grid, to derive a 'describing function' for the drag 'response' to turbulence. This describing function is the central element needed for the calculation of structural response in the drag direction. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1970
- Accession Number
- AD0704121
Entities
People
- David Surry
Organizations
- University of Toronto