Comparison of temperature and velocity spectra in a slightly heated turbulent plane jet

Temperature and velocity spectra obtained experimentally in a slightly heated turbulent plane jet are compared. A hot-wire X-probe and a cold-wire probe were positioned 508 mm from a 12.7-mm-wide 250-mm-high nozzle to determine velocity and temperature fluctuations in a jet flow (with nominal speed 9 m/sec and nominal temperature relative to ambient 25 K) at sampling rate 333 Hz for about 60 sec. The results are presented graphically and discussed in terms of an analogy between the spectral distribution of the temperature fluctuations and that of the turbulent kinetic energy. This analogy, noted in a heated turbulent boundary layer by Fulachier and Dumas (1976), is confirmed for the self-preserving region of the turbulent plane jet, where the temperature spectrum depends on all three velocity fluctuations, especially near the centerline.