In this paper a new flow facility for studies of pulsating flows is described. The pulsating flow is generated by means of a rotating valve and the flow is quantified through a newly developed flow measurement module accurately measuring the phase averaged flow distribution. The measuring probe of the module consists of a hot/cold-wire pair that enables both the mass flux and recovery temperature to be measured simultaneously. Calibrations of both the hot and cold wire are done in-situ in steady flow by means of a Pitot tube and a thermocouple. Moreover, the phase averaged flow distribution can be obtained by an automatic traverse of the measuring probe across the pipe cross section in both the radial and azimuthal directions. In the paper we exemplify and describe the flow properties, using the new flow measurement module, both in steady and pulsating flow.

Vortex flowmeters are commonly employed in technical applications and are obtainable in a variety of commercially available types. However their robustness and accuracy can easily be impaired by environmental conditions, such as inflow disturbances and/or pulsating conditions. Various post-processing techniques of the vortex signal have been used, but all of these methods are so far targeted on obtaining an improved estimate of the time-averaged bulk velocity. Here, on the other hand, we propose, based on wavelet analysis, a straightforward way to utilize the signal from a vortex shedder to extract the time-resolved and thereby the phase-averaged velocity under pulsatile flow conditions. The method was verified with hot-wire and laser Doppler velocimetry measurements.

The inflow to and outflow from turbochargers are highly complex and, in particular, pulsating. Nevertheless, most studies of turbocharger performance are conducted under steady conditions. Hence, there is a great interest in determining and understanding turbocharger performance maps under pulsatile conditions. The highly complex flow field constitutes a challenge for time-resolved flow measurements by means of conventional measurement techniques. In a recent paper by Laurantzon et al [Meas. Sci. Technol. 20 123001 (2010)], time-resolved bulk flow measurements under pulsatile conditions have been obtained via wavelet analysis of the signal from a vortex flow meter. Here, this method has been used in order to obtain time-resolved performance maps based on the mass flow both upstream and down-stream of the turbine. The results show that the turbine has a large damping effect on the mass flow pulsations, but that the pulse shape is to a high degree preserved while passing through the turbine, and that the time-dependent filling and emptying of the turbine case make the quasi-steady assumption invalid, if the whole turbine stage is considered.

Instantaneous velocity and temperature measurements by means of hot-wire and coldwires have become a standard technique used in almost every fluid dynamic research laboratory. Nonetheless, when it comes to compressible flows in applied fields, there seems to remain a need for clarification on which temperature is actually measured by a cold-wire and which temperature a hot-wire senses as its fluid temperature. The present paper reviews the view present in the literature and presents additional experimental evidence, that it is indeed the recovery temperature that is measured by a cold-wire and that this is also the temperature needed to compensate hot-wire readings in nonisothermal compressible flows