On the Development of an Efficient Sliding Mesh Interface for the Harmonic Balance Method, Part II: Effects of Casing Treatments on the Aerodynamic Damping of a Compressor Blade

In order to enable the Harmonic Balance (HB) method for efficiently capturing the non-linear effects of complicated configurations such as casing treatments, we introduce an algorithm for the coupling of non-conforming mesh topologies across domain boundaries in a series of two papers. In this second paper, we demonstrate the novel sliding mesh method’s relevance for the design of modern transonic compressor rotors with casing treatments. In order to allow for a flutter assessment of the rotor with the flow solver TRACE a specific mesh topology for the frequency domain approach to connect stationary cavities with the moving rotor domain is introduced. It shows no significant impact on the flow characteristics of interest. HB results are successfully verified by means of time domain simulations (TD) with respect to average flow quantities and unsteady flow characteristics. Both methods clearly illustrate that a casing treatment not only affects the average flow field but also significantly changes the unsteady flow viz. the aerodynamic damping of the rotor. By providing the same prediction quality for more than one order of magnitude less computational resources than the TD approach the novel method enables an efficient industrial design process for such configurations with HB.