Entrainment and spreading of turbulent shear flows

Abstract

Over the last decade there has been a renewed interest in understanding the entrainment process in turbulent shear flows [5]. Even though there are differences between the way different shear flows (such as jets, wakes, boundary layers and shear-free flows) develop [14] , the origin of these differences is not clear. Here, employing experimental data from an axisymmetric turbulent jet and a turbulent boundary layer, we present conditional velocity profiles at the tubrbulent/non-turbulent interface (TNTI) and quantitatively reveal the differences encountered by the two different shear flows. In particular, we examine the role of radial velocity in the entrainment process which is present in j..