Temperature fluctuations and anomalous scaling in low-Mach-numbercompressible turbulent flow

Temperature fluctuations in a low-Mach-number compressible turbulent fluid flow are studied. It is demonstrated that, due to compressibility and external pressure fluctuations, the anomalous scaling may occur in the second moment of the temperature field. The cause of the anomalous behavior is a compressibility-induced depletion of the turbulent diffusion of the second moment of the temperature. It is shown that temperature fluctuations in compressible fluid flow (without thermal instability) can be excited only by external pressure fluctuations. Experiments are suggested for the observation of the excitation of the temperature fluctuations.