The development and use of multi-hole pressure probes for measurements in time-varying flows is outlined. An FFT-based dynamic calibration technique is used that permits enhanced dynamic response from relatively robust probes. To enable high turbulence flows to be measured, including flow reversals, a probe with an extended cone of acceptance is described including validation in a variety of turbulent and smooth flows. The pressure-based probes can be used for a range of measurements that would normally be outside the scope of HWA, LDA and PIV. Some applications are described.
Every individual who has ever driven behind or adjacent to a truck in rainy weather is very aware of the hazards of truck spray for highway driving. Truck spray during wet weather creates poor visibility for all drivers. Several devices have been created that are supposed to limit the spray from large trucks. This report describes an evaluation of spray reduction devices that were tested at lower vehicle speeds and at higher vehicle speeds. Four configurations were tested, as follows: configuration 1 - 1997 Freightliner tractor-trailer without spray reduction device, configuration 2 - 1997 Freightliner tractor-trailer with spray reduction device, configuration 3 - 1985 Freightliner tractor-trailer without spray reduction device, and configuration 4 - 1985 Freightliner tractor-trailer with spray reduction device. The 1985 Freightliner was an older non-aerodynamic combination, and the 1997 Freightliner was considered to be aerodynamic. Results indicate that the addition of the spray reduction device to the 1985 Freightliner slightly reduced spray at lower speeds, but did not provide a benefit at higher speeds. Addition of the spray reduction device to the 1997 aerodynamically superior Freightliner did not result in a significant reduction of spray at any speed tested, compared with the 1997 Freightliner tractor-trailer without spray reduction device.