Flow Over a Three-Dimensional Horizontal Forward-Facing Step

Three-dimensional flow effects on forced convection heat transfer in a channel with stepwise-varying width

“…Axial velocity profiles are compared to published values at three representative positions, namely immediately upstream of the step (X/s=19.09), downstream of the step tip (X/s=20.08) and at the channel outlet (X/s=60). The streamwise velocity profiles along the Y direction in the middle of the channel spanwise direction are in very good agreement with the respective values of [11], as shown in Fig. 3.…”

“…Experimental results in configurations that are closely related to the present one could not be found, therefore suitable numerical solutions were sought instead. Barbosa-Saldaña et al [11] investigated the threedimensional confined laminar flow over a forward-facing step, which is a configuration that exhibits the closest resemblance to the unit cell of the present work. Therefore, for validation purposes, the dimensions of the unit cell and the boundary conditions are adjusted, as a no-slip condition (wall) is placed at the base upstream of the step instead of a symmetry boundary, so as to match the corresponding configuration found in [11].…”

“…Fig. 3a indicates the flow configuration, as also the nomenclature used in [11]. The step height s is taken equal to half the channel height H (H=2s) and the step is placed at a distance l=20s downstream of the channel inlet, while the channel total length L and width W are L=60s and W=4s, respectively.…”

“…The topology of this streaky pattern was found to be closely related to the longitudinal vortices, as a periodic pair of counter rotating vortices was always located between two paths of fluid entrainment. Barbosa-Saldaña et al [11] also investigated numerically the threedimensional laminar forward-facing step flow using a finite volume method. They examined the effect of increased Reynolds number on the magnitude and location of the salient and tip vortices detected immediately upstream and at the edge of the step respectively, but they did not mention the emergence of any periodic longitudinal vortices.…”

“…The three-dimensional nature of separated flows in the case of a geometrical confinement generates a complex velocity field manifested by the formation of distinct vortex structures [8][9][10][11]. Stüer et al [8] used the hydrogen bubble technique and particle tracking velocimetry to visualize the laminar three-dimensional flow ahead of a forward facing step.…”