DOI: 10.1615/ICHMT.2015.THMT-15
ISBN Print: 978-1-56700-427-4
ISBN CD: 978-1-56700-428-8
Relating characteristics of turbulence with pressure spectrum using time resolved PIV
RESUMO
For many fluid engineering applications, measurements of velocity and pressure distributions in the systems are of fundamental importance in order to provide insight into the flow characteristics. In this study, the instantaneous pressure was estimated by using non-intrusive technique from measured 2D particle image velocimetry (PIV) data. Afterward, the pressure spectrum was evaluated by taking fast Fourier transformation (FFT) of the pressure profile. The spectral slope of -7/3 was found in the inertial sub range of pressure spectrum. Also, the pressure based integral length scale and Taylor microscale were estimated from autocorrelation function and pressure spectrum respectively. The ratio of pressure integral length scale to the velocity integral length scale was a constant of about 0.67 and the pressure Taylor microscale was approximately 79 per cent of the velocity Taylor microscale for low Reynolds number. The experimental results were compared with existing theory and DNS results. A new method is proposed to evaluate specific energy dissipation rate based on the pressure spectrum. It was observed that the values of specific energy dissipation rate were over predicted by 25 per cent than those calculated from velocity spectrum.