Designing experiments to test closure hypotheses

The unique problems confronting turbulence modelers and experimenters who wish to directly test closure hypotheses are reviewed. Particular attention is paid to the problems presented by systematic errors in the experimental data. Some of the sources of these errors in thermal and laser-Doppler anemometry techniques for measurement are also reviewed, as are problems common to all techniques. The discussion is illustrated by examples from the authors' own work in axisymmetric jets.