APPLICATION OF TRIPLE DECOMPOSITION TECHNIQUE IN NEAR-WAKE MEASUREMENTS OF A SQUARE CYLINDER

Abstract

The flow properties and wake structures behind bluff bodies have fascinated researchers for many years. The Reynolds decomposition is a very common technique to approach these problems. However, some researchers tackle such problems with an alternative technique known as the triple decomposition. Since the flow structure of a bluff body comprises large-scale organized motion, the time-varying component in the wake region of a bluff-body flow consists of a periodic component (coherent structure) that can be distinguished from a random (incoherent) component. In the present study, incoherent turbulent flow structures in the near-wake region downstream of a square cylinder have been studied by employing triple decomposition. It was observed that the main incoherent turbulent kinetic energy production occurs in the region with the same width of square cylinder. Moreover, it was demonstrated that while a vortex is developing from one edge with maximum incoherent streamwise stress, the initiated shear layers from the other edge exhibit a maximum in incoherent transverse stress production.