A comprehensive method of estimating the performance of axial flow steam and gas turbines is presented, based on analysis of linear cascade tests on blading, on a number of turbine test results, and on air tests of model casings. The validity of the use of such data is briefly considered. Data are presented to allow performance estimation of actual machines over a wide range of Reynolds number, Mach number, aspect ratio and other relevant variables. The use of the method in connection with three-dimensional methods of flow estimation is considered, and data presented showing encouraging agreement between estimates and available test results. Finally ‘carpets’ are presented showing the trends in efficiencies that are attainable in turbines designed over a wide range of loading, axial velocity/blade speed ratio, Reynolds number and aspect ratio.

The application of acoustic backscattering, for measuring near-bed high-resolution profiles of suspended sediment concentration and particle size, has advanced substantially in recent years. To interpret these suspension observations and link them with the hydrodynamics, similarly detailed flow observations would be advantageous. In the present work backscattering from suspensions of marine sediments has been investigated to examine the potential of using the backscattered signal to also measure high-resolution near-bed vertical profiles of horizontal current flow. The approach adopted has been to attempt to utilize the temporal coherence in the suspension field, and to employ cross correlation of the backscattered signal between pairs of horizontally separated transducers to measure current profiles. To investigate this technique a series of laboratory measurements have been conducted for a variety of experimental arrangements, and the outcome from these measurements is reported in the present work. An examination of the suspension field has been conducted, and cross correlations between pairs of transducers investigated. Using cross-correlation time lags, current profiles have been calculated, and the results assessed using laser Doppler flow measurements. Comparison of the acoustic cross-correlation flow measurements with the Doppler reference measurements show a high degree of agreement, and strongly support the use of the cross-correlation approach to accurately measure vertical profiles of the mean horizontal current.