Multi Location LDA Measurement in a Shock Tube,
Abstract
We describe a new experimental technique for obtaining fully-resolved measurements of the vector velocity field u(x,f) throughout a four-dimensional spatio-temporal region in a turbulent flow, and present examples of results obtained from of its application in a study of the fine-scale structure and dynamics of turbulent flows. The method uses fully-resolved four-dimensional scalar field imaging measurements to extract the underlying vector velocity field from the exact conserved scalar transport equation. The procedure for accomplishing this is summarized. Results from a test case in which an actual measured turbulent flow scalar field xi(x,f) is advected numerically by an imposed flow field allow a careful validation of the technique and its potential accuracy. Further results obtained by applying this new technique to extract the underlying structure of the vector velocity, vorticity, and tensor strain rate fields in a turbulent flow are also presented. These indicate that this scalar imaging velocimetry technique provides a novel means for experimentally studying the detailed physical structure and spatio-temporal dynamics of the dissipative scales of motion in turbulent flows. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 23, 1992
- Accession Number
- ADP008909
Entities
People
- Dariush Modarress
- Thomas Hoeft