One of the main fields of application for TRACE is the aeroelastic analysis of turbomachinery components. Flutter and forced-response predictions are indispensable when innovative blade designs are developed on the basis of CFD. Aerodynamic design goals (e.g., low flow losses) and aeroelastic constraints (e.g., flutter stability) are often concurrent objectives, hence the need for fast prediction methods for flutter and forced response. In the Numerical Methods department, several preprocess tools as well as computational and post processing methods have been developed over the past years to meet these requirements.
In this area, a unique feature of TRACE is the possibility to employ several simplifying assumptions in order to find a trade-off between computational effort and accuracy. For a flutter analysis one can use the module linearTRACE which, for small amplitude vibrations, rapidly calculates aerodynamic damping and stiffness. If the user has reasons to believe that non-linear effects have to be taken into account, she can use the non-linear unsteady module, e.g. for forced response. Moreover, the Numerical Methods department is currently working on the extension of the harmonic balance method for aeroelastic applications. The goal is to efficiently achieve estimates for the impact of the interactions with arbitrarily many blade rows, thus circumventing computationally expensive full annulus simulations.
Abbildung 1: Blade eigenmode of a turbine rotor