Progress in Predicting the Development and Transition Onset in Free Shear Layers
Abstract
During this reporting period, the problem of transition in the arbitrary two-dimensional free shear layer was resolved within the context of the predictive approach based on the dissipation criterion. A formula for the transition Reynolds number was derived showing explicitly its increase with speed ratio, fast-side Mach number and total temperature ratio for the two streams. Comparison with data shows that qualitative and approximate quantitative predictions with this formula can be made. The theory for the arbitrarily asymmetric wake was also worked out, both for application to the non-equilibrium shear layer transition problem and for practical use in fluid- laser geometries. In the limit of the symmetric wake close to the trailing edge, the results are in excellent agreement with Goldstein's earlier theory. Application of this theory may assist in improving the design of high-energy fluid lasers. One of the many basic fluid mechanical problems inherent in these devices is the prediction of laminar-turbulent transition along the shear layer separating two co-flowing streams; initially laminar flow in this layer is expected due to the small size of the working-fluid and additive-injectant nozzles. In this period the theory addressed homogeneous (same chemistry) mixing across a two-dimensional laminar shear layer of arbitrary 'jump' conditions. A predictive formula was derived and was satisfactorily tested against the available data. (edc)
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1980
- Accession Number
- ADA214781
Entities
People
- Anthony Demetriades
Organizations
- Montana State University