10 février 2022

Webinar Mehdi Vahdati

Mehdi is the Principal Research Fellow in the Thermo-Fluids Division. He has over 30 years of experience in developing numerical models for aerodynamics and aeroelasticity. Prior to his current position, he led the aeroelasticity group at Rolls-Royce Vibration University Technology Centre (VUTC) at Imperial College. During this time, his group developed the aerodynamics and aeroelasticity Code AU3D, which is used at all Rolls-Royce sites (UK, USA, Germany and India) as the only code for aeroelastic analysis. Every Rolls-Royce engine since the late 1990s has utilised this code during its development including the entire Trent engine family, this has led to considerable savings for Rolls-Royce. He was awarded the position of Rolls-Royce Research Fellow in Imperial College (first person to receive this award) for my services to the company. He has been a partner in major UK/European turbomachinery projects. His research topics include: development of CFD algorithms for internal and external flows, development of numerical aeroelasticity (FSI) models, aeroelastic modelling of gas turbine components (fan, compressor, turbine and seals), turbulence modelling using machine learning, applications of machine learning in turbomachinery, aerodynamic and aeroacoustics modelling of drones (UAVs), aeroelastic behaviour of wind turbines.
Review of Computational Aeroelasticity of Turbomachines

Abstract: Aeroelasticity is a branch of applied mechanics that studies the interactions between the inertial, elastic and aerodynamic forces while an elastic body is exposed to fluid flow. In other words: ‘How does a solid body react to fluid forces acting on it, and how does the flow change in response?’ Unsteady turbulent high-speed compressible flows often give rise to complex aeroelasticity phenomena by influencing the dynamic behaviour of the structures on which they act. Under certain conditions, the energy transfer from the fluid to the structure can cause excessive vibration levels and structural integrity may be compromised. The problem is particularly severe for gas turbines where virtually all blade rows are susceptible to aeroelasticity effects either by inherent self-induced motion (flutter and buffet) or by response to aerodynamic flow distortions and blade wakes (forced response).Along with foreign object damage (FOD), High-Cycle Fatigue (HCF) vibration of aerofoils from Fluid-Solid Interactions (aeroelastic excitation) is a major concern for the safety and reliability of all turbomachinery. With demands for reduced greenhouse gas emissions, the need for cleaner more efficient turbine technology has become critical. To achieve significant improvements in fuel efficiency new novel design concepts are required. The new concepts will usually involve higher aerodynamic loading with lightervand more flexible structures, and hence are more prone to aeroelastic issues. The objective of this lecture is to present aeroelasticity issues and CFD modelling techniques for turbomachinery. The outline of the lecture is:
1. What is aeroelasticity?
2. Examples of aeroelastic events
3. Explain aeroelastic phenomena using a 2D airfoil
4. Basic mechanical vibration
5. Aeroelastic models used in CFD
6. Aeroelastic events for fan blades on aeroengines

10 février 2022, 16h3017h30
Please contact F. Romano and J.-P. Laval for the link