Interactions between viscous and transonic effects in air flow around a laminar wing were investigated computationally by means of the solution of unsteady Reynolds-averaged Navier-Stokes Equations. The subject is important from the point of view of applications of Natural Laminar Flow technology in modern, economically efficient passenger aircraft. The research was focused on simulations and analyses of influence of turbulence induced by micro vortex generators on intensity of harmful transonic phenomena like strong shock waves and buffet. Two ways of modelling of the effects of turbulators-the micro vortex generators were taken into consideration. The first way consisted in resolving the shape and inclination angle of the generator in the grid over airfoil and setting the non-slip wall boundary condition on the surface of the generator. The second way, taking advantage of the BAY model of vortex generator, was implemented on orthogonal grid without the need of resolving the shape of the vortex generator in the grid. Calibration of the BAY model was aimed at producing similar distribution of vorticity and velocity circulation behind the model of the vortex generator, as obtained for the grid-resolved model of the vortex generator. The calibration procedure resulted, however, in overestimated turbulisation of the boundary layer in the BAY model, compared to the effects of the grid-resolved vortex generator. The flow simulations indicated, however, that turbulisation of boundary layer induced by micro vortex generators can reduce or eliminate the oscillation of strong shock wave and buffet in off-design conditions and that further adjusting of the BAY model is an efficient strategy for modelling the interactions between viscous and transonic effects in air flow around a laminar wing.

Solutions for turbulisation of a part of laminar boundary layer upstream of shockwave on laminar airfoil in transonic flow were investigated by means of solution of Unsteady Reynolds-Averagd Navier-Stokes equations using as a closure the four-variable Transition SST turbulence model of ANSYS FLUENT solver. This turbulence model has the capability of resolving laminar-turbulent transition occurring in undisturbed flow as well as under the influence of flow-control devices. The aim of the work was to investigate possibilities of improvement of aerodynamic characteristics of laminar wing of a prospective transport aircraft in adverse conditions characterised by occurrence of a shockwave over a laminar-turbulent transition region with separation of laminar flow under the shockwave. The subject is important for application of laminar flow technology, offering economic and environmental advantages due to decreased friction drag, into civil transport aviation. Natural laminar-turbulent transition in the investigated conditions takes place with occurrence of "laminar separation bubble" under the foot of a shockwave and the resulting shockwave is intensive and prone to unsteady oscillations, the "buffet" phenomenon, limiting operational range of flight parameters. In order to counteract the harmful effects of natural laminar-turbulent transition in transonic flow two types of turbulators, placed upstream of the shockwave, were investigated. One of them consisted of delta-shaped vortex generators, producing chordwise-oriented vortices. The other consisted of rectangular micro-vanes, perpendicular to flow and to airfoil surface producing vortices of rotation axes oriented spanwise. Effectiveness of both types of turbulators was investigated for varying height and their location on airfoil chord. Both types of turbulators have proved their effectiveness in tripping laminar boundary layer. The specific effects of the tutbulators, different for each type occurred in the region where laminar separation takes place on clean airfoil. As a result, the changes of lift and drag were different for each type of turbulators.

Abstract. The concept of Smart Micro Vanes (SMV) has been developed and investigated

An important goal of the TFAST project was to study the effect of the location of transition in relation to the shock wave on the separation size, shock structure and unsteadiness of the interaction area. Boundary layer tripping (by wire or roughness) and flow control devices (Vortex Generators and cold plasma) were used for boundary layer transition induction. As flow control devices were used here in the laminar boundary layer for the first time, their effectiveness in transition induction was an important outcome. It was intended to determine in what way the application of these techniques induces transition. These methods should have a significantly different effect on boundary layer receptivity, i.e. the transition location. Apart from an improved understanding of operation control methods, the main objective was to localize the transition as far downstream as possible while ensuring a turbulent character of interaction. The final objective, involving all the partners, was to build a physical model of transition control devices. Establishing of such model would