The structure of the flat plate incompressible smooth-surface boundary layer in a low-speed water flow is examined using hydrogen-bubble measurements and also hot-wire measurements with dye visualization. Particular emphasis is placed on the details of the process of turbulence production near the wall. In the zone 0 < y+ < 100, the data show that essentially all turbulence production occurs during intermittent ‘bursting’ periods. ‘Bursts’ are described in some detail.The uncertainties in the bubble data are large, but they have the distinct advantage of providing velocity profiles as a function of time and the time sequences of events. These data show that the velocity profiles during bursting periods assume a shape which is qualitatively distinct from the well-known mean profiles. The observations are also used as the basis for a discussion of possible appropriate mathematical models for turbulence production.

Although gamma delta T cells have been postulated to act as a surveillance mechanism that eliminates transformed or otherwise damaged cells, little is known about tumor recognition by gamma delta T cells, including the Ags that are recognized and the molecules that present them. Previously, we described human gamma delta CTL that recognize the autologous B cell lymphoma. Here we report that these gamma delta CTL lyse heterologous cells transfected with the tumor Ig lambda chain gene. Furthermore, the lambda chain is recognized as processed peptide in an Id-specific manner. T cell recognition does not involve classical MHC molecules, but it could be blocked by Abs directed against the heat shock protein grp75. These findings show a specific gamma delta T cell response to a highly polymorphic Ag such as tumor Id and implicate heat shock protein as a molecule required for recognition.

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