Small-scale intermittency and local anisotropy in turbulent mixing with rotation

Yi Li
2011 Journal of turbulence  
The statistics of the velocity gradient and the gradient of a passive scalar in rotating turbulence are studied using Lagrangian stochastic models. Models for the velocity gradients are derived generalizing the approach proposed in Chevillard and Meneveau [Phys. Rev. Lett. 97, 174501(200)], whereas the scalar gradients are described using the model proposed by Gonzalez in Phys. Fluids 21, 055104 (2009). The non-Gaussian and anisotropic statistics of the gradients are analyzed, and compared with
more » ... , and compared with available results in the literature. It is found that the models reproduce the observation that rotation tends to reduce small-scale intermittency for both velocity and scalar gradients. The models predict the skewness of transverse velocity gradient components in the perpendicular plane and its non-monotonic dependence on the rotation rate. The models also reproduce the anisotropy in the scalar gradient at intermediate Rossby numbers. Furthermore, we show that the anisotropy is reached at an intermediate rotation rate, and the maximum coincides with a transition in the relative importance of the self and cross production terms for the scalar gradient.
doi:10.1080/14685248.2011.613398 fatcat:bqf4d2znsbclbnek2uesy5euiu