Computational simulation of vortex generator effects on transonic shock/boundary-layer interaction

Abstract

T HE present work describes a theoretical simulation of the effects of a vortex generator row ahead of a shock/boundary-layer interaction zone. The row is represented by parameters characterizing the Law of the Wall/Law of the Wake structure of the turbulent boundary layer. This model is then integrated into a previously developed twodimensional computational code that utilizes an appropriate triple-deck theory of a nonseparating shock/bbundary-layer interaction. The results imply that the shape factor reduction effect associated with a vortex generator can have powerful, favorable effects on the local and overall interactive properties, but can also promote earlier incipient separation in the immediate vicinity of the shock foot. ContentsThe influence of shock/boundary-layer interaction on a supercritical wing can extend significantly downstream within the boundary layer and thus adversely affect global aerodynamic properties. This negative influence may be reduced by means of the boundary-layer control device known as the vortex generator, which delays separation by promoting mixing between the freestream and the boundary layer. The present paper describes a method that computationally simulates the gross spanwise-averaged two-dimensional effects of a vortex generator row located ahead of an unseparated shock/boundary-layer interaction zone such as that found on a supercritical wing (see Fig. 1). The model of this situation is based on fundamental Law of the Wall/Law of the Wake relations for the incoming turbulent boundary layer, combined with a triple-deck theory of the subsequent interaction zone.

Effect of Microvortex Generators On Seperated Normal Shock/ Boundary Layer Interactions

“…Downstream of the SBVGs the main shock resembles that seen in the uncontrolled interaction, except that the foot is distinctly smaller. This contraction of the foot appears to confirm the conclusions of Inger and Siebersma [17] that VGs reduce the size of the interaction region. The boundary layer thickens significantly at the main shock position for both devices.…”

“…This observation is of interest because it ties in with shock-control methods such as passive devices [2,[9][10][11], active control [2] using blowing [2] or suction [12,13], and 2-D [14,15] or 3-D bumps [16], which work by generating compression waves that smear the shock-induced pressure rise. However, Inger and Siebersma [17] showed numerically that VGs upstream of a shock energize the boundary layer, thereby reducing the shape factor and increasing the pressure gradient and shock strength across the interaction. This paper presents an investigation into the effect of SBVGs upstream of a separated shock/boundary layer interaction (SBLI) and aims to determine whether such devices can have a shock weakening effect.…”

Survey of control techniques to alleviate repercussions of shock-wave and boundary-layer interactions

“…These vortices can be shed by inserting traditional or sub-boundary layer vortex generators into the flow [129]. Through their research in transonic flow, Inger and Siebersma (1989) showed that placing vortex generators upstream of the contact point energizes the incoming boundary layer wave [130]. As a result, the pressure gradient around the contact zone rises, ultimately creating a strong shock.…”

“…(Passive control) [105,121,[129][130][131][132][133][134][135][136][137][138][139][140][141][142][143][144] Very efficient in suppressing the separated shear layer by energizing the incoming boundary layer through vortices.…”