Invariant Analysis of Vortical Delta Wing Flow Using the Extended Optimal Triple Tensor Decomposition

Abstract

Vortices and vortex breakdown flow structures over a multidelta wing configuration are often analyzed by applying flow field invariant analysis techniques from critical point theory and flow topology research. In particular the three invariants of the velocity gradient tensor are used to classify and analyze flow fields, mainly for the assignment of vortical flow regions and assessment of their stability. In this work, the extended optimal triple tensor decomposition is applied to the vortical flow field delivering new tensor fields which allow to recalculate the rate of strain and rotation tensors in an associated basic reference frame. These new tensor fields contain separated distinct flow properties. After retransformation into the original coordinate system, flow field invariant analysis techniques applied to these newly derived tensor fields provide further insights into the dynamics of vortical flows over delta wings.