The kurtosis of the methane concentration distribution on the jet centerline is plotted as a function of z/r Q Examples of correlation functions and power spectra for methane concentration fluctuations at three different axial downstream distances in a methaneair jet.

The power spectral density of turbulent wall pressure fluctuations was measured in a tube downstream of a model arterial constriction. The flow parameters were varied from steady flow to conditions simulating human arterial pulsatile flow. Within the experimental uncertainty (±10 percent in characteristic turbulent frequency, fo, and ±25 percent in absolute rms pressure fluctuation amplitude), turbulent flow at the peak of systole produces wall pressure fluctuations identical to those of a steady flow at the same Reynolds number.

Roasting meat is modeled as a nonlinear variable‐property heat transfer. the results are compared with conventional recommendations, and quite a variance is found for roasts which are either long or flat. the effects of initial temperature, aftercooking, and other parameters are evaluated. A companion paper considers optimizing the roasting process for a specified desired doneness profile.

In this paper we discuss the application of numerical optimization techniques to the process of roasting, which essentially is heat treating meat under a variety of ambient temperature conditions. The doneness of roast, as measured by the distribution of maximum temperatures achieved through the meat, is taken to be the objective for optimization, using cooking temperatures and times as the process variables. Cooking beef roasts of varying weights and shapes are the examples considered. Additional considerations for optimization, such as minimum cooking time and energy used, have also been considered. Direct search methods were found to be m s t suited for objective functions with a highly varied topology, as were encountered in this problem. The optimal results, compared with the conventional cooking recommendations, show that superior heat treatment can be effected by using numerical modeling and optimization techniques.

An important secondary goal has been the development of new experimental techniques having high spatial and temporal resolution for the investigation of concentration and velocity in variable density flows. These diagnostics are required in order to gain insights into the temporal behavior of turbulent mixing processes. 2.