Effects of heat of reaction on homogeneous compressible turbulence

Direct numerical simulations (DNS) or homogeneous compressible turbulent reacting flows are conducted to investigate the effects of heat of reaction on the solenoidal and the dilatational turbulent motions. Consistent with the previous theoretical results, it is shown that the heat of reaction does not have a significant effect on the low order moments of the solenoidal velocity. However, the variances of dilatation, pressure, temperature, and density, increase significantly due to heat release. Also, the magnitudes of the skewness and the kurtosis of dilatation increase significantly as a result of heat of reaction. The high negative values of the dilatation correspond to localized structures with low probability of existence. The heat of reaction also enhances the amplitude and the frequency of the oscillations of the pressure-dilatation correlation. Examination of the energy transfer among rotational and compressive components of the kinetic energy and the internal energy indicates that the energy of the reaction is transferred to the compressive component of the kinetic energy by the pressure-dilatation correlation. The advection term then transfer the energy from the compressive component of the kinetic energy to its rotational component. While the interactions between compressive component of the kinetic energy and the internal energy are significant, those between the rotational and the compressive components of the kinetic energy are relatively weak.