Periodic Reporting for period 2 - TEAMAero (Towards Effective Flow Control and Mitigation of Shock Effects in Aeronautical Applications)
Reporting period: 2022-04-01 to 2024-06-30
Europe’s future in aviation is closely tied to the goals of Flightpath 2050 – Europe’s Vision for Aviation, an EU report from the HighLevel Group on Aviation Research. These goals include a 75% reduction in CO2 emissions per passenger kilometre to support the Air Transport Action Group target , a 90% reduction in NOx emissions, and noise emissions reduced by 65%. "The aviation industry is entering an era of new technology that will bring a new generation of intelligent aircraft in the market. The new generation of airliners will allow longer maintenance intervals and repair changes as well as better health monitoring and prognostics of maintenance needs."
Achieving goals defined in Flightpath 2050 – Europe’s Vision for Aviation will require major improvements in efficiency, which for aircraft means reduced weight and better aerodynamic performance, based on high-performance wings, control surfaces and turbomachinery blades, where transonic ow is common place and the formation of shock waves is the key aerodynamic challenge. In particular, the interaction of shock waves with boundary layers is the primary performance-limiting factor across all of these ow fields. Thus, knowledge of the interaction of shock waves with boundary layer is essential for the development of more efficient aircraft and engines.
The problem is that increased aerodynamic forces can lead to flow separation and reductions in engine and airframe efficiency. In such cases, flow control is needed to maintain the system’s performance. Novel designs can also increase the extent of laminar flow and this means that ow-control devices need to operate in a laminar or transitional regime, which requires a better understanding of their function and their interaction with flow transition. Of course, improvements to their effectiveness will have a direct and positive impact on airframe and engine performance. It is because these modern geometries are increasingly complex that we have to really understand and so be able to control three-dimensional flows, especially the three-dimensional shock wave boundary layer interactions (SBLI)
The TEAMAero project has the following objectives:
(1) to improve our fundamental understanding of the physics of Shock Wave Boundary Layer Interaction (SBLI), including three-dimensionality and unsteadiness;
(2) to identify the flow domains best suited to flow-control device installation;
(3) to develop flow control methods using wall transpiration, vortex generators and surface treatments to delay the onset of separation or to control shock oscillations, and
(4) to develop novel numerical methods for predicting the effects of SBLI.
Achieving goals defined in Flightpath 2050 – Europe’s Vision for Aviation will require major improvements in efficiency, which for aircraft means reduced weight and better aerodynamic performance, based on high-performance wings, control surfaces and turbomachinery blades, where transonic ow is common place and the formation of shock waves is the key aerodynamic challenge. In particular, the interaction of shock waves with boundary layers is the primary performance-limiting factor across all of these ow fields. Thus, knowledge of the interaction of shock waves with boundary layer is essential for the development of more efficient aircraft and engines.
The problem is that increased aerodynamic forces can lead to flow separation and reductions in engine and airframe efficiency. In such cases, flow control is needed to maintain the system’s performance. Novel designs can also increase the extent of laminar flow and this means that ow-control devices need to operate in a laminar or transitional regime, which requires a better understanding of their function and their interaction with flow transition. Of course, improvements to their effectiveness will have a direct and positive impact on airframe and engine performance. It is because these modern geometries are increasingly complex that we have to really understand and so be able to control three-dimensional flows, especially the three-dimensional shock wave boundary layer interactions (SBLI)
The TEAMAero project has the following objectives:
(1) to improve our fundamental understanding of the physics of Shock Wave Boundary Layer Interaction (SBLI), including three-dimensionality and unsteadiness;
(2) to identify the flow domains best suited to flow-control device installation;
(3) to develop flow control methods using wall transpiration, vortex generators and surface treatments to delay the onset of separation or to control shock oscillations, and
(4) to develop novel numerical methods for predicting the effects of SBLI.
The multi-disciplinary training platform has brought together 12 beneficiaries, top-rank academia, research centres and industrial stakeholders and 6 partner organisations, actively involved in top-level research in the fields of transonic flows with a focus on shock wave boundary layer interaction, advanced optical measurement methods, high-speed imaging, mathematics, numerical methods, multi-objective optimisation and mechanical engineering.
The 15 Early Stage Researchers involved in the project have carried out numerical simulations and experimental investigations for shock wave boundary layer interactions in various configurations including wings, inlet ducts and transonic fan or compressor stator.
Several results have been achieved during TEAMAero project.
(1) Development of numerical methods used to simulate transonic interactions using Direct Numerical Simulations, both in Cartesian and curvilinear coordinates, to improve turbulence modelling in harmonic methods for shock-induced separated flows in turbomachinery applications, to examine unsteadiness and the underlying mechanism in a transitional shock reflection with separation, to investigate the ability of the Partially-Averaged Navier- Stokes method to reproduce transonic buffet.
(2) Experimental campaigns to understand unsteady flow effects and development of measurement techniques to study the time scale in a transition process of a natural laminar boundary layer and to investigate unsteady flow conditions in a turbulent shockwave-boundary layer interaction.
(3) Flow control methods: porous bleed control in mitigating the negative effects of shock-wave/boundary-layer interactions, separation-bubble-shaped shock control bumps, conical shaped artificial corner separation bodies, surface roughness effect.
(4) Investigations of unsteady effects due to the shock-boundary layer interactions in transonic compressor cascades. Numerical and experimental study of Reynolds number and surface roughness effect on shock wave unsteadiness in a rotor and a stator cascade. Transonic Cascade TEAMAero was optimized and its performance was validated experimentally.
The 15 Early Stage Researchers involved in the project have carried out numerical simulations and experimental investigations for shock wave boundary layer interactions in various configurations including wings, inlet ducts and transonic fan or compressor stator.
Several results have been achieved during TEAMAero project.
(1) Development of numerical methods used to simulate transonic interactions using Direct Numerical Simulations, both in Cartesian and curvilinear coordinates, to improve turbulence modelling in harmonic methods for shock-induced separated flows in turbomachinery applications, to examine unsteadiness and the underlying mechanism in a transitional shock reflection with separation, to investigate the ability of the Partially-Averaged Navier- Stokes method to reproduce transonic buffet.
(2) Experimental campaigns to understand unsteady flow effects and development of measurement techniques to study the time scale in a transition process of a natural laminar boundary layer and to investigate unsteady flow conditions in a turbulent shockwave-boundary layer interaction.
(3) Flow control methods: porous bleed control in mitigating the negative effects of shock-wave/boundary-layer interactions, separation-bubble-shaped shock control bumps, conical shaped artificial corner separation bodies, surface roughness effect.
(4) Investigations of unsteady effects due to the shock-boundary layer interactions in transonic compressor cascades. Numerical and experimental study of Reynolds number and surface roughness effect on shock wave unsteadiness in a rotor and a stator cascade. Transonic Cascade TEAMAero was optimized and its performance was validated experimentally.
The TEAMAero project allowed for the improvement our fundamental understanding of the physics of shock wave boundary layer interactions for various Reynolds number. By analysing the time scales of a shock-wave boundary layer interaction, the low-frequency unsteadiness is characterised. A possible link between the presence of non-linearities over the separated shear layer and the low-frequency unsteadiness was found. TEAMAero has gained an insight into the physical mechanisms governing shock-induced corner separation and have a new understanding of unsteadiness and its main sources.
The developed numerical methods and innovative measurement techniques (e.g. flexible wall-pressure sensor array or multi-sensor hot-wire probe) allow for detailed analysis of shock wave boundary layer interaction in basic flow configurations and wings or transonic compressor cascades.
Investigated flow control methods lead to reduction shock wave oscillations, separation bubble size and aerodynamic performance improvement.
The developed numerical methods and innovative measurement techniques (e.g. flexible wall-pressure sensor array or multi-sensor hot-wire probe) allow for detailed analysis of shock wave boundary layer interaction in basic flow configurations and wings or transonic compressor cascades.
Investigated flow control methods lead to reduction shock wave oscillations, separation bubble size and aerodynamic performance improvement.