Holographic Interferometric Survey of Boundary Layer Transition in an Axisymmetric Free Convection Thermal Boundary Layer.
Abstract
Unique optical data from the laminar and transition regions of an axisymmetric free convection thermal boundary layer are presented. The boundary layer encompasses a vertically oriented right circular cylinder kept at a constant wall temperature and suspended in a quiescent air environment. Pulse laser holographic interferometry was used to obtain a measurement of the temperture distribution through the boundary layer. Schlieren methods are used to photograph the boundary layer to provide a qualitative description of the transition region. An approach is outlined to find an approximate numerical solution for the temperture distribution through the boundary layer. Intergral equations are developed for a differential control volume within the boundary layer after which assumed velocity and temperature distributions are used to reduce the intergral equations to first order non-linear differential equations. The differential equations are non-dimensionalized and numerical techniques are used in an attempt to obtain a solution. Quantitative data from the laminar region resulted in a discrepancy between theoretical and experimental evaluation of a local Nusselt number. Qualitative observation of the transition region reveals a fringe reversal phenomena that could possibly be associated with the fundamental mechanisms of transition. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1979
- Accession Number
- ADA079880
Entities
People
- Gregory S. Meserve
Organizations
- Air Force Institute of Technology