SIG Lead: Adriano Cerminara, Sheffield Hallam University.

Domain expertise: Hypersonic transition, boundary-layer receptivity and stability, hypersonic aerothermodynamics, transpiration cooling, DNS.

SIG Co-Lead: Kshitij Sabnis, Queen Mary University of London.

Domain expertise: Experimental high-speed aerodynamics, optical diagnostics, shock/boundary-layer interactions, flow control.

The UK Hypersonic Transition Special Interest Group (SIG) brings together researchers across the UK to advance understanding, prediction, and control of transition to turbulence in hypersonic flows. Hypersonic transition critically affects vehicle aerothermal performance and stability, compromising its structural integrity. However, accurate transition prediction and control remain challenging research areas.

The SIG provides a platform for collaboration between theoretical, numerical, and experimental experts from UK academia and industry. Activities include workshops, periodic technical meetings, data sharing, and coordinated studies, all aimed at consolidating UK expertise and driving innovation in hypersonic technology.

The activities of the UK Transition SIG will culminate in the definition of a dedicated hypersonic transition flight experiment, including flow conditions, configuration and diagnostics, to provide valuable information on transition prediction and control. By fostering collaboration, knowledge exchange, and training opportunities, the UK Hypersonic Transition SIG will position the UK scientific community among the world leaders in this critical area of hypersonics research.

SIG Lead: Tobias Hermann, University of Oxford.

Domain expertise: Aerothermodynamics.

SIG Co-Lead: Jon Binner, University of Birmingham.

Domain expertise: Materials.

The Materials and Fluid–Thermal–Structure Interaction (Mat-FTSI) Special Interest Group (SIG) coordinates UK efforts to understand and validate coupled fluid–thermal–structural behaviour of materials in hypersonic flight. At high enthalpy and high-speed flow conditions, aerothermal loads, chemical surface reactions, material degradation and structural deformation can interact to modify vehicle geometry and aerodynamic performance. These effects cannot be reliably predicted using uncoupled models or validated using scaled ground testing alone. Therefore, the research questions of interest to this SIG are:

• To what extent can flight experiments be used to validate predictive numerical tools?
• How large are the differences between flight and ground testing when simulating coupled FTSI phenomena?
• Which physical processes dominate geometry evolution and performance changes during hypersonic flight?
• What measurements are required to discriminate between competing modelling approaches?
• How can the model outcomes  be used to optimise materials, structures and manufacturing choices?

The UK currently lacks a coordinated cross-disciplinary network encompassing the fields relevant to Mat-FTSI. This SIG aims to address the gap by bringing together researchers from aerothermodynamics, materials, structures, manufacturing, instrumentation and flight experimentation.

As part of the UK Hypersonics Network, one long-term objective is to establish capability that directly supports future UK hypersonic flight experiments. The specific deliverable of this SIG is an instrumented, thermally loaded fin flown on a sounding rocket platform. Such a configuration provides measurable aerothermal gradients, structural deformation sensitivity and opportunities to study oxidation, ablation and geometry evolution under realistic flight conditions. However, the purpose of the SIG is not to define a single flight experiment from the outset, but rather to build the technical foundation required for future flight-testing activities. Different locations on hypersonic platforms will see very different conditions during flight and materials & structure solutions will be needed for all of them.