There are no measurement techniques for turbulent flows capable of reaching the versatility of hot-wire probes and their frequency response. Nevertheless, the issue of their spatial resolution is still a matter of debate when it comes to high Reynolds number near-wall turbulence. Another, so far unattended, issue is the effect of temperature fluctuations - as they are, e.g. encountered in non-isothermal flows - on the low and higher-order moments in wall-bounded turbulent flows obtained through hot-wire anemometry. The present investigation is dedicated to document, understand, and ultimately correct these effects. For this purpose, the response of a hot-wire is simulated through the use of velocity and temperature data from a turbulent channel flow generated by means of direct numerical simulations. Results show that ignoring the effect of temperature fluctuations, caused by temperature gradients along the wall-normal direction, introduces - despite a local mean temperature compensation of the velocity reading - significant errors. The results serve as a note of caution for hot-wire measurements in wall-bounded turbulence, and also where temperature gradients are more prevalent, such as heat transfer measurements or high Mach number flows. A simple correction scheme involving only mean temperature quantities (besides the streamwise velocity information) is finally proposed that leads to a substantial bias error reduction. © 2014 Springer-Verlag Berlin Heidelberg.
The influence of temperature fluctuations on hot-wire measurements in wall-bounded turbulence / Orlu, R.; Malizia, F.; Cimarelli, A.; Schlatter, P.; Talamelli, A.. - In: EXPERIMENTS IN FLUIDS. - ISSN 0723-4864. - 55:7(2014), pp. 1781-1789.
Data di pubblicazione: | 2014 |
Titolo: | The influence of temperature fluctuations on hot-wire measurements in wall-bounded turbulence |
Autore/i: | Orlu, R.; Malizia, F.; Cimarelli, A.; Schlatter, P.; Talamelli, A. |
Autore/i UNIMORE: | |
Digital Object Identifier (DOI): | http://dx.doi.org/10.1007/s00348-014-1781-x |
Rivista: | |
Volume: | 55 |
Fascicolo: | 7 |
Pagina iniziale: | 1781 |
Pagina finale: | 1789 |
Codice identificativo ISI: | WOS:000339874100001 |
Codice identificativo Scopus: | 2-s2.0-84925483684 |
Citazione: | The influence of temperature fluctuations on hot-wire measurements in wall-bounded turbulence / Orlu, R.; Malizia, F.; Cimarelli, A.; Schlatter, P.; Talamelli, A.. - In: EXPERIMENTS IN FLUIDS. - ISSN 0723-4864. - 55:7(2014), pp. 1781-1789. |
Tipologia | Articolo su rivista |
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