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The structure and dynamics of vorticity and rate of strain in incompressible homogeneous turbulence. (English) Zbl 0933.76035
The structure and dynamics of vorticity $$\omega$$ and rate of strain $${\mathbf S}$$ are studied using direct numerical simulations of incompressible homogeneous isotropic turbulence. In particular, we present characteristics of the pressure Hessian $$\Pi$$, which describe non-local interaction of $$\omega$$ and $${\mathbf S}$$. Conditional Lagrangian statistics which distinguish high-amplitude events in both space and time are used to investigate the physical processes associated with their evolution. The dynamics are examined on the principal strain basis which distinguishes vortex stretching and induced rotation of the principal axes of $${\mathbf S}$$. The latter mechanism is associated with misaligned $$\omega$$ with respect to $${\mathbf S}$$, a condition which predominates in isotropic turbulence and is dynamically significant, particularly in rotation-dominated regions of the flow.

##### MSC:
 76F05 Isotropic turbulence; homogeneous turbulence 76F65 Direct numerical and large eddy simulation of turbulence
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